How do you do that?!

Im wondering, how do you change your avatar in the game? Ive seen people with skull masks and with different fur color and Im wondering how do they do it. PLease tell me!

http://tale-of-tales.com/TheE

http://tale-of-tales.com/TheEndlessForest/

You can find instructions if you click forest magic, tell me if there is something you don't understand