Good start, the best way to learn PS, is to keep playing with it. You'll eventually get the hang of it. Also if you need any help, this Forum is an excellent resource. I see you've been playing with the smudge tool. Oh yeah, also a bit of advice, blur the edges on a paste over (pit-bison), or select the area and contract the selection a pixel or two, then inverse the selection, and delete or blur; then the overlay will look much better!
Good Luck on you PS fun!!