Making a head texture with sunhat.

I don't know where to put the sunhat. Any guidance pictures?

I'd say make it in a separate file, just make rest invisible and then you have an easy hat you can adjust and use on future heads as well. It will also make it easier to paste it over your current head and get the fit just right. You can go in afterward and add shadows for optimal grooviness. Easiest would be a simple arc or ellipse for the hat line, but a jaunty angle might give it more character. Getting the seam in back smooth will be a big factor in making or breaking your hat.