Ok i will have another look at lua but i know the basics of it
more you will be sure to have the knowledge , less you will have it 
You should also use the gta 5 natives snippets, they come in very useful
I have learnt Lua literally I know how to do if else if else functions print etc so is that what I needed to learn?
Your natives are completely incorrect, you’re writing them as if it was c# (i think), also you put local SET_PLAYER_MODEL(Player player, Hash model) you put local as if you were trying to use it as a variable??? which should be something you already knew if you actually know how to do lua. You’re also trying to use natives in a server side script, which wont work, you need to trigger an event which the client can register then change the skin, so basically this would be what you put server side: TriggerClientEvent("changeskin", source) then client youd do:
RegisterNetEvent("changeskin")
AddEventHandler("changeskin", function()
--write whatever you want it to do here
end)
so if you did the command, youd trigger the event which the client would pickup and then youd have the natives there
Ok but I know this me I watched the videos 3 times and understand now