This download looks like a map. You need to place it in your maps folder inside the Garry's Mod folder.
You should end up with a directory structure similar to below
Don't know where the Garry's Mod folder is or how to extract zip files? See more useful installation tips.
Scp049, giustomax, pecata985, azov_wars, Harambe Uchiha, poorMrbumblepuss, bblue4350, Demon201666, matheussantanasantiago1.0, diegotomeldan31, diegotomeldan31, dennisbondarenko2009, xXolpe, Lenny, comcom, Uncle Mânzoliu, Bomba, NussElite93, Foster [TR], GHOSTLY SNIPER, hashemishahrodih000, 4am.joshsummer, tawseeftahmeed656, YOKIMORO, gabr13l-, Balkan Guy, cubic_control, danika20053, relmore, tonywan2000, 1yodaman, bibkare, 小夜JK, agustintorne, ilmingostyle, henzboss, Prologik, Endeavor_Z, Pixcraftgamer, Pixcraftgamer, Ewout, jeffy21, Alex, Alex, Alex, Alex, Jirro, gold94chica , Reverend V92, Rasko +2 others
