here's a tutuorial i create:
Ok, first, make a
NEW layer, do not duplicate the layer. Then there is options, click on transparency.
Ok, the next step, click on your new layer, you should see some kind of checkerboard on the layer bar So now, Draw anything you want on that layer, and that will block out some of the Transparent part
Next, after you are done drawing whatever you want, you delete the original/first layer below the New Layer. Then you will end up with the checkerboard on your layer with your drawing. the checkerboard pieces will be your invisible parts.
After that, you save the flat image as a png or gif (png has more qualitly), so you type "whatever".gif
Save it on the first option you see (top)
When you are done, upload your head texture. And then ingame, it should look like this.
I hoped you learned something