It's the same with player skins as gun skins, but different folders.
C:\Program Files\Steam\steamapps\< name >\condition zero\czero\models\player
I guess that's the folder you need to add the "gign" "urban" etc. folders.
Go to disk c
C:\PROGRAM FILES\STEAM\STEAMAPPS\NAME\CONDITION ZERO\CZERO\MODELS\PLAYER
you will see the files list
player skins place into the files