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.
GENTLEMEN SPY[ASİL TR], x iTRiiNitYy v, Nightstorm1003, MisterAlpha, allahu akbar, TheScout, gaben newell, metamophic, bielskipiotr1234, GhaniGamerXD, RazetheBeast, roy13al, Squeeze, D1nickle, GOLT[TH], FZ.Crazy.BCLM, www.andrews, tar0630, l.q.q.u.i.n.n.7.7, VoNiTo101, Circonvolutor, Tekno Rage Gamez, IM.DEATH, gedovicskrisztian, aaaaaa13569, [DWM] The BLU Guy, durpachudurp, Histoire, Jatv13, fenixx234, Xshamanc, [CO2] Daniel7D3v, stormap9, pstratto, Sex KAMAZ, #The_Monkey, mrjungles, ItsPoopie, OrdePlayer, vector343mariobros, xXSONICTHEHEDGEHOGXx, Big Fat Meanie, funky winky, ✯ErichGrooms➊✯, Pipas, Cute_Bonnie1987, manguyman, freddy the animatronic, minebroliam, BlueFireFury +84 others
