First, you need to extract the ExeFS and RomFS from the game's ROM. Please refer to other guides online, you'll find it on Google. Here is an overview of the most important folders and files (click the arrow to expand).
Unity-specific files.
Metadata: Contains type information for classes, methods etc.Asset files are included in every Unity game.
The folder we're primarily interested in.
ab/: Contains Unity AssetBundle files which store the game's assets.data/: Data in .json format.native_data/: Mostly binary data in game-specific format (file formats similar to Super Mystery Dungeon).