Follow steps

1. Open Steam go to Community then Workshop and type Garry's mod

2. Type in Search "playermodel" not "player model" already "playermodel" you can put after playermodel name like some of anime characters or other things for example: "playermodel Obito Uchiha" to find it easier

3. Next step search and find model that you like the most, when you find it click button Subscribe

4. Now open Garry's mod and go to any map Click "C" Button on Keyboard and up on the left click "Player Model" select your Model and Kill yourself (you can use "kill" command in console for instantly death) to make your skin appear


enjoy :)