Even with tutorials its not very easy it takes weeks of practice, to begin with search this site for tutorials. Then your going to need to download a program such as wc3viewer in order to convert blp files from the warcraft mpq to jpeg formats. Then comes the hard part and that would be skinning outlining areas to match the location of the model exactly otherwise you´d painted\drawn a nose were the chin of the model is for instance, i find the light effect to be most hard weres there is light or shadow or where there is hard armor or just soft skin you´ll need the correct tools to do this and you can´t just randomly burn here and smudge there, not a lot of ppl can skin and not a lot of ppl can skin any good.