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.
hexer54539, hexer54539, hexer54539, qqqtrs, houyamchada, mossesx, ManderSkat123, ManderSkat123, TH38Ki113R, FemPyro❤, jullianbouchet, retuif, paceyroy086, lovesavage72, Xeren, Véradun Er Taral, Ivan Dickevich Rekanov | sups.gg, ., HitmanGhost, Dormento, caron.paul