Help Installing Custom Skin

So, I opened up the citizen_sheet.vtf file in “hl2/materials/models/Humans/male/Group01” and edited it using my photoshop powers, and saved it as a VTF file. I placed it back in Hl2, in groups 1, 2, and 3, replacing all of the originals. It didn’t work on Gmod, so I created a Group01 folder with the new skin and put it in “garrysmod/garrysmod/materials/models/” and noticed that there wasn’t a “Humans/male/Group1” folder as the tutorial had promised, so I created new folders with the same name and placed it so it was “garrysmod/garrysmod/materials/models/Humans/male/Group01”. However, the skins still don’t show up both when I spawn citizens and change my player model. Any help would be appreciated.