The basics are this:
1) Make sure that you have a backup of the Strive game files somewhere (doesn't matter where, even the original zip is fine)
2) Put the AricsExpansion mod in the AppData/Mod folder (where all mods go)
3) Copy and Paste the folder that says App Data into the App Data/Roaming/Strive folder (ie: the folder right before the mod folder you just used)
4) Copy and Paste the other folder into the Strive folder with the actual game files. Override anything it asks you to.
5) Go into the game and activate Aric's mod from the mod panel. Restart the game when it asks you too. I'd recommend JUST activating Aric's first and make sure that everything seems to be working fine before trying to add anything else (though there are details on other compatible mods or how to make some compatible all throughout this thread).