If you are updating, delete the old files from your Mods folder first
Extract the contents of the downloaded zip file
Place the extracted folder directly in your Mods folder
Folder location: Documents > Electronic Arts > The Sims 4 > Mods
Enable Script Mods and CC in your TS4 game settings
Note: Script Mods should not be more than 1 subfolder deep from your root (Mods) folder.
This works: Documents/Electronic Arts/The Sims 4/Mods/Basemental Gangs
This doesn’t: Documents/Electronic Arts/The Sims 4/Mods/Some Folder/Basemental Gangs
This mod conflicts with other mods installed that adds custom venues to your game, if you have Zerbu´s Get To School/College mod, LittleMsSams more buyable venues, delete their Venue Lists. (The Venue List in this mod includes their venues as well, so you should be good to go).
This mod does NOT replace Basemental Drugs, but is an add-on to Basemental Drugs. Do not delete Basemental Drugs prior to installing this mod.