Need Help With Vice City Mod.

Remember MasterBlaster from Beyond Thunderdome? Well, imagine i'm Blaster and you're telling me how to install a mod called Night Long (zombie mod) onto my Vice City game and some of its cars from The GTA Place website. I know i gotta use a zip program but which one? After i download and unzip i have no idea in hell where to put these files and or do they have to replaces files such as one cars has to replace another? I managed to add cars to my Mafia game and it worked! All input is appreciated. Remember, Blaster.