Place the yourhero123_suits-X.X.X folder in your BepInEx/Plugins folder. Make sure the yourhero123_suits folder is in the same folder as yourhero123_suits.dll.
After launching the game with the mod once, a config file is generated. In this file you can disable individual suits from being loaded, as well as ignore any !less-suits.txt file and attempt to load all suits (which is useful if you have another mod that helps manage lots of suits).
You can add .png files to the yourhero123_suits folder to add new suits as long as both the host and clients have the same files.
You can add a .json file in the advanced folder with the same name as your .png file in the yourhero123_suits folder to enable additional features like emission. Place additional texture maps in the advanced folder.
Add a "PRICE" key to your advanced .json to put a suit in the store rotation. See Glow.json for an example of adding a suit with emission that must be purchased from the store.