The process of learning the basics of a new topic:
1 - Get a reason to learn about it: "I don't really have a sense of smell, but I've been thinking about omegaverse pheromones lately, so I should learn the basics."
2 - Read a few Wikipedia articles to build a skeleton for future knowledge: "Yeah, I knew about the overlap between taste and smell, but FOUR HUNDRED different types of receptors? Interesting! Also, why is it so hard to find categorization schemes? Why are there no links? WHY DOES SYMMETRY HAVE A SMELL?!? Ugh, am I going have to read about perfumes? I HATE perfumes!"
3 - Find some intermediate level sources: "Okay, an article on the history of categorization schemes ... and why they all failed? That's ominous."
4 - Figure out what preconceptions are getting in the way: "Okay 400 different types of receptors, and almost all scents are actually a complex synthesis of multiple of them, plus we STILL don't understand the relationship between chemical structure and scent? And a lot of relationships between scents seem to be cultural? I'm not going to get a nice categorization scheme, am I? And I can't actually smell well enough to understand any of this intuitively, so how CAN I increase my knowledge here?"
5 - Experiment: "Okay, if I look at this list of perfume terminology, can I start to get an idea of the language ITS using and the relationships it suggests? Can I make a cross-referenced list?"
6 - Get a better idea of scope: "Okay this is going to be 2-3 days of work, and while it WILL help, it will only give me about a third of what I'm looking for. Is this really worth a week of tedious sorting? Especially since there won't actually BE similar lists for unpleasant odours to complete my model?"
7 - Refocus: "I don't actually NEED a complete model here, do I? I started off wanting to know just enough about scents to start worldbuilding some omegaverse stereotypes relating to them. So as long as I know enough to not use near-synonyms as names for different groupings (ie. knowing that "resinous" and "balsamic" HEAVILY overlap), and can create some reasonable groupings, not knowing the rest is FINE!"
8 - Success! Slightly more knowledge has been obtained!
Did you know that the sense of smell is the only one of the (five, well-known) senses that people haven't been able to categorize? No wave-lengths, no grouping by types of receptors.
Did you know that smell is really hard to test because the various receptors HATE GROWING IN LAB CONDITIONS? And people can't figure out why? They refuse to grow in the proper positions, or sometimes at all.
Did you know that 'animalic' is a stupid term and I hate it? They couldn't even pull out 'faunal' to match with 'floral'? Pathetic.
Did you know that 'caprylic', 'hircine', or just 'goat-like' was a weirdly tenacious smell category while they WERE trying to categorize odours? Like, I get that they probably have a pretty distinct smell, but you're dividing things into 4 fundamental categories, and you're sure one of them HAS to be 'specifically THIS animal's stench'?