The package files ? You don't need to open them. Just copy into your mods folder. If they are rar files you need to donload 7zip or winrar.
me too, when i click on ''open'' a message pop up on my screen sayin ''this file does not have an app associatted to performed this action...'' i don't know what to do
@victooo_2 Don't open the file, that is if it's a .package file. Just put it inside your Mods folder, and the game will know what to do with it.
Custom content downloaded as a .zip file needs to be extracted before using, which you should be able to do by double-clicking. If the file comes in .rar or .7z format, you'll need a third-party tool such as 7-Zip (Windows) or Unarchiver (macOS).
