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.
MaksRus89, ]3oOoJKT_/_ ]_UD, Джеб Керман, Rjwii_1, Белок, ksaweryiewa64, karopa4173, friend, hugoplayerhd, PONDPTK, pjbarbee82, ☢SCP-049☢, ☢SCP-049☢, brk2981, Henry, kubiakk487, hollow knight, hollow knight, 888delfina, ADI, dennsya1000, pilot778, max12984, max12984, Dfreeman67, Ash Vietnam, sprite1444, D-pro gamer, david, The Gamer Police {NCR}, The Gamer Police {NCR}, Чивабчичи, swiogame, jularatpraphant, rjt.ten.hove, MYKDWAKILLE, iphitos9, ★SIVA★, SIDTEAM, Вафли добрый песик, ytelizator, kralicek.vasiksp, Adler Fleischmann, mitsushi.mzm, 카운, England, Stepan 505, d.milosevic2007, ЕГОРЫЧ, Ɇnder_ℱighter +160 others
