This download looks like a lua file. You need to place it in your lua 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.
Dances with Ducks, Twitch.TV/NotoricTV, ГарикМод, wirus12313, Замкнутый, impacT, Artfulspy, ., joalalfred21, Cameron | Reddrp, [LOS] GLaDOS, Higgins, flocefai, fez, Curry, Kurma, Bio, Deus Sex, Krzysiu, XAZOR, pacino80, DeathMachine128, [GL]Aa TitAnzZ aA, Жмышенко Валерий Альбертович, Muggy, SealSAURUS REKTS, Doktor 12, Florian Bos, ❤ C R E O N I X ❤, fantome, GalactiK, [SRP]Mipastu, GreyNade, RobertMer, Thekodex12, Grozger Zasrogtiveslin, Richard Roy, DJReFor, 18gradenbewolkt, João, Scoop, Fancy Mango, shixthug, civil rights leader flavor flav, haagse24uur, TwoFactor, PonyEB, Makarov, thewildbirdmedic, firefox450 +7 others
