How do i setup a skin?

This skin has two folders, it has to do with changing the appearance of a person. Is it supposed to have 2 folders? Do I have to refresh Gmod? Where do i put it? The folders are called materials and models. I know i need to put both of those folders in the second garrys mod folder. What am i doing wrong?

Note: I have noticed that the game notices that it has been spawned. You just cant see it. The phisics gun is working when I aim at it, it can be picked up and droped.

What exactly are you trying to skin?

Changing the appearance of a person

I meant specifically.

The Person?

OMFG you just have to copy these folders to your garrysmod directory (steam/steamapps/youraccountname/garryssmod/garrysmod) and your skin is installed.