~first, get a picture you want to cut.
~there are lots of "select tools" to use for cutting a certain face/head of a picture
~you can use the lasso tools, marquee tools, magic wand tool,
and more that i haven't still discovered
~you must practice selecting objects to select a certain part you want to cut to make you cutted picture perfect
~after you selected the head/face, you right click it then you can choose layer via cut or layer via copy; and there's a lot of ways instead of this.
~after you have cut the head/face, you can Drag it to another picture body you want.
~since you are a beginner, keep practicing on selecting
~what i said were the basics of photo editing