ACSE (or Awesome Cobra Script Extender) is a mod that does not offer any particular game feature, but enables other mods to include custom gameplay modifications to Cobra engine games. You are probably looking for this mod because some other mod requires having ACSE installed.
ACSE works as a standalone Cobra engine content package and can be installed and removed without modifying any game files. Content packages need to be installed in the ovlData folder of the game.
If you download this mod manually, unzip the contents of the Zip file into the Planet Zoo/Win64/OvlData/ folder.
If you have ACSE installed manually before we suggest you use Vortex to manage your mods.