when i put all of my pngs, the head is covered by the hair. i want to put the head in front but I cant

I don't know if you already solved your problem, but what you have to do is go to the layer you want on top of the others and with the E key you can raise a layer, with the Q key you will lower a layer, if you don't have layers it won't lower any, I recommend creating 3 layers to be able to move the pngs