This will help me find the exact installation steps for you.
: Usually require moving files into a "Mods" or "Data" folder within the game's directory. SPECIAL990_PACK2.rar
: Use a utility like WinRAR , 7-Zip , or The Unarchiver to open the archive. Right-click the file and select "Extract Here" or "Extract to SPECIAL990_PACK2/". This will help me find the exact installation steps for you
