This download looks like an addon. You need to extract the downloaded zip and put the addon folder in your Garry's Mod addons 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.
jokkuxx, qsidannaqsi, Aigoo, TheGamerCreatio, alex B, KiNERKiNERKiNER, navi! <3, Shrek24, sunny1233xd, cristgomena, SOSIGMAN25, İSKENDER BÜYÜK, fearofcrows, Sssss, juliusbido50, MilesBEB002, [LOS] Kammerun, TOSHIBA, Average edm enjoyer, hmpoweredman123, jalalinoyan, dwane trock jonson venom, holly_official_edits, metropro726, alechavez73, notme18938, manuelcondoriconde35, BeenerMcMestizo, JuanUwU, unityazwt.g6, dannalfredaclao2008, MonsterKiller, x_broken_trustt_x, alfredodestructor10, Matcha, quentinromeo02, The Star-Crew 5, iloveyou, XysharookPL CASEDROP eu, E d g a r W o l f, WolfGangKarl, Local Idiot, Azure, Alex, VAL, Modern, Midnight Danny, danielabalice02, emoji0629, essijohanna_88 +1196 others
