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.
₡ŧℱ➁ώ ₱ტﻸໂℜ, tapok, Draggfive, Blue Crimson, Blue Crimson, BrochATron, DAYMAN, TSQ>Kezzy, BOT Lucas, Futrex, Patrick, Code_Alpha, Natalie Dormer, ディック, Alex Episode