This specific release follows the folder structure format for Rain World. It is the first publicly available release.
Extract the zip file into RainWorld_Data/StreamingAssets/mods
To use this in other games, copy the DLLs inside of the "patchers" folder into (game)/BepInEx/patchers.
The generated Extensibles DLL will be created in (game)/BepInEx/plugins after the first run.