[YoYo123]

I don't understand your current question.. There is only one function that can set a player's skin and that is SetPlayerSkin(playerid, skinid). The Random concept means: Let's take 6 numbers from 0 to 5 and chooose a random number between those. If 0 is chosen, than SetPlayerSkin(playerid, skinid), if 1 is chosen, set it to another skin etc.

EDIT: If you still don't understand tell me exactly what you don't understand or we won't understand you either.