Any advice for someone who wants to do their own setting in the bronze age? (Hope this isn't a silly question)
-Remember that technological ages are ways to describe regional tool use forms rather than a strict linear evolution of improvements. When we refer to "the bronze age" broadly, what's being talked about is a technological period in parts of Europe, Asia, and North Africa in which bronze was the dominant material for tool production. Not everywhere with access to bronze metallurgy had a discrete 'bronze age' where this metal dominated toolmaking, and not just because they had something 'better' introduced before that could occur. A region's technology adapts to what resources are available (natively or by trade) and its geography, among other things.
I say this because Eurocentric looks upon history tend to focus first on the technological and political achievements of West Asian civilizations that laid the groundwork for European history as we know it, and then on European history as we know it, and so a lot of people are taught this very linear model of technological advancement, often with an underlying tone of an almost predestined arc of greatness. Stone age -> Copper Age -> Bronze Age -> Iron Age -> Dark Ages -> Renaissance -> Modernity. This is not some inevitable trajectory, this is the trajectory of one part of the world. There are Reasons metal use developments go in the copper->bronze->iron order in places where all three metals had dominant historical use. Copper has a lower melting point than iron, is abundant, and is much more durable than metals like gold or silver, and neolithic era kilns were entirely adequate for making copper tools, but not iron. So we have a "copper age" where metal tools are in demand. Bronze working comes as a development from copperworking, as bronze is an alloy of copper and tin, both of which have fairly low melting points. It requires specialized knowledge and techniques (with the tin and copper being handled separately before forging), so bronze metallurgy is not simply an immediate expansion of copperworking. This is seized upon where metal tools are in demand because bronze is much sturdier than copper, and so it becomes dominant and we have a 'bronze age'. Terrestrial iron is extremely abundant but must be smelted before use, and smelting it requires substantially higher temperatures than copper, tin, or bronze. So this required changes in forge technology that could generate hotter fires (in addition to techniques like introducing carbon to the process and ability to remove impurities) in order for ferrous metallurgy to take hold.
Basically what I'm saying is it's diminishingly unlikely that a society is able to create iron tools before it's able to create bronze tools (unless this technology and all requisite knowledge to use it was introduced from elsewhere, or unless you have magic in your setting that can generate really really hot fires. OR unless we're talking about the cold forging of meteoric iron, which is already in a workable state (unlike terrestrial iron which must be smelted from ore) and was used for a few thousand years before anyone started smelting iron). These processes all developed out of building on each other and knowledge being disseminated. But that doesn't Mean these technologies will naturally and inevitably come one after another. Andean and later Mesoamerican civilizations utilized both copper-tin and copper-arsenic bronze alloys and used this bronze for both utilitarian and artistic goods, but these bronze tools (as well as copper ones) were used alongside stone tools, and bronze tools did not have the overwhelming impact there that they did in parts of Eurasia (unfortunately this is an area of relatively limited easily accessible scholarship so I can't just off the cuff list any Specific hypotheses on why, beyond "the Americas and Eurasia had very different geographical and political and material circumstances, Eurasian styles of war and transportation created unique demands to specialize in metal tools for use in weapons/armor/vehicles/etc and fostered a dependency in them via competition with similar societies, while navigating the Andean and Mesoamerican political environments/systems of transport/warfare simply did not necessitate specialization in metal tools, and instead demanded a greater variety of material technologies be at play for utilitarian toolmaking"). Development of iron smelting did not occur in the precolonial Americas whatsoever, but iron from the Innaanganeq meteorite was used in cold forging and traded across great distances by the Thule people and their descendants for centuries. There is no linear "advancement", there is just what resources are available, what a society's needs are to survive/thrive in a specific geographical/social/political environment, where and how trade networks can be structured, and how local, regional, continental, and global history plays out.
This wikipedia map is good to look at. This is the overall division of subsistence/society types in 2000 BCE, in the midst of what was broadly the Eurasian Bronze Age.
Note that state societies are relatively few and far between, and are a tiny minority of societies in the world, and not all of them were utilizing bronze tools at this time (and on the other end, the area of bronze working comprises all sorts of societies who are in interaction by geographic proximity and trade, or in a couple of places in east and southeast Asia where the practice may have developed independently by this time). Keep in mind that your whole world is not going to be in its "bronze age" and there's going to be lots of other stuff going on, and many of your bronze age societies are going to have direct contact and trade with non-bronze working societies.
Unless you're making a direct earth analogue with direct analogues to real life civilizations, your focus should first be on the material circumstances that facilitate mass creation and utilization bronze tools. You should have at least a basic map (and I think you should always have at least a basic map for large scale worldbuilding, or at the very least know where the things you're talking about exist in relation to the equator), and you should have an idea of where tin and copper ores are present on that map.
-If a major part of your setting is specialized into bronze toolmaking and is in a 'bronze age', that means people in this area have access to both copper and tin. And tin is a rare mineral so this means that there's long distance trade networks supplying tin to a large area of bronzeworking societies. Large, robust trade networks of that kind are generally going to have large, robust societies with an outsized hand in facilitating them, though a full spectrum of settled and some nomadic societies will contribute to this trade system. Think about where in the world bronzeworking techniques were first developed independently, and have a map in mind to figure out how this technology would have spread.
Here's a map I pulled from wikipedia of diffusion of bronze metallurgy, a a map that details tin deposits in more detail, and a map of possible tin trade routes
[source for the second map, I would read the whole article]
You can see what a long distance tin would have to be moved, and how the locations convenient for long distance sea trade become hubs for their zone of interaction. You need to have this sort of thing in mind when crafting your setting- where can tin be mined? What routes would the tin trade take? This goes for any other metal as well (and also should be kept in mind for any resource spread or obtained through trade in general), but copper is much more abundant and so its sources will not have as dramatic a sway on how bronze metallurgy disseminates and how bronze age societies structure their trade.
This sets up other questions to take into consideration. A place that's a convenient trading hub for getting tin to societies that demand it may develop an outsized sway on its zone of interaction, and be highly contested, or important for major civilizations to bring under their control or political influence/allegiance.
Trade is always easiest by water. No matter how well developed road infrastructure is in a given place, goods are going to be more difficult to transport (and therefore expensive) if they have to be moved mostly or entirely overland (except for like, short distances) rather than mostly or entirely over rivers and seas. In places on the far fringes of your Bronze Age region where tin imports would have to be moved a long distance purely on land, bronze goods may be limited to special purposes or to upper classes, with the average person using stone tools (class stratification may impose this to varying degrees on places with better access to tin as well). Large areas where trade has to occur completely over land will also slow the spread of new technologies (and cultural transmission in general), and in our history, this speed of transmission further depended on available domestic animals. Horses monumentally shaped human society wherever they were in use as domesticates, in some part because they facilitated relatively rapid movements of People and Ideas and Things over very long distances on land (camels play a similar or overlapping role in some places) (horses were also huuuuge for warfare but I digress). Places without pack/cart/mount animals also had robust land trade systems that moved goods over vast distances, but moving goods overland purely by human labor imposes different constraints on trade than movement supported by beasts of burden (and does open up some different opportunities- a human can't carry nearly as much as a horse, but they're smarter than the horse and can navigate more types of terrain and don't eat as much).
For your big states with outsized regional power, they need to be placed appropriately. Every state society within these periods fell within the subtropics or tropics with their long growing seasons, and in places suited for large scale settled agriculture, meaning with dependable access to fresh water one way or another (mostly by major rivers that facilitated large scale irrigation). The civilizations of Mesopotamia and Egypt fell within largely arid climates, but their agrarian cores were built up along rivers with huge fertile floodplains, and beyond that developed and utilized irrigation technology to better capitalize on their water sources. This allows for huge sedentary populations to be supported, which in turn can support the existence of complex states, which in turn help facilitate control over trade via centralized power/bureaucracy to manage it, large bodies of laborers to extract, produce, and move trade goods, military to protect assets and expand sphere of influence via conquest or threat of conquest, etc. Minoan civilization existed on an island and there's nothing particularly outstanding about its agricultural viability, but its prime location as a trade hub seems to be what facilitated its power, appearing to dominate trade in much of the Mediterranean at its peak. They appear to have exported luxury/specialty goods and moved tin and other key trade goods along and benefit in turn from resources that were limited on the island of Crete, which otherwise may not have been able to sustain a state society of this scope. Capitalizing on this system made them very powerful for a time (though unfortunately we haven't decoded their language, and so have very little definitive understanding of their government and how it interacted with trade). You should be thinking about stuff like that where you're placing some of your major players.
I'm ultimately assuming you want a setting that more or less resembles the Eurasian bronze age, in terms of the scope of societies, the number of people in interaction, etc, and the Mediterranean sea was crucial to the development of that technological period. Seafarers in this overall period didn't have the ability to make journeys across entire oceans, which requires a whole litany of achievements and cultural knowledge in navigation practices and sailing technology (large boats carrying goods around the open Mediterranean in the bronze age required teams of rowers). So having this sort of large but (relatively) narrow sea that connects to the open ocean, spans a substantial range, and has plenty of islands as stopping points is fundamental to how this period was able to play out. Of course you can also take entirely different routes and have a large period in its 'bronze age' that spread its technology primarily along oceanic coasts, secondarily along large rivers, and more slowly over land, but that's going to look very different (and odds are, is going to make this bronzeworking region smaller due to having less avenues to move tin around quickly and cheaply).
As usual the best way to do it is to research the bronze age(s) of real life, specific bronze age societies, etc to see how these ideas work in action. And I think the best way to use real life research for a constructed setting is to pay the most attention to how things interconnect, because that's ultimately what's going to give you the tools to make something feasible without it being a direct copy of real life. When you learn about a material, you ask questions like "where does it come from? who's extracting it? who's moving it over long distances? who's facilitating that movement?". ETC. Every answered question gives you more questions and you could go down this road for an eternity without running out of things to ask, but getting used to thinking and making connections like that is vital.
It is Impossible as a singular author to have a region the size of the one in that trade map and every single one of its moving parts worked out (much less An Entire World). You could spend your entire life just fleshing out every possible aspect of a bronze age trade power civilization on an island the size of Crete. But just knowing the kinds of questions you have to be asking and developing an intuition for how things interconnect is half the battle.
