Narrative structures
A narrative structure is basically the "set-up" of how a story is told.
Most stories/texts/fairytales/films etc. start at the beginning. It has a middle (where a conflict usually is presented) and then after that, a solution to the conflict, which is the end. This type of narrative structure is called a linear structure. It's a structure which makes it very easy to understand the plot.
There are also stories and films that begin in the middle of the story. Or at the end. This would be the opposite of the linear structure - a nonlinear structure, or as I was taught it was called: "in medias res", which is latin for "into the middle of things". A nonlinear structure can start with a flashback for example, or it can be a reverse chronology (end - middle - beginning).
