you won't be able to put a door skin on yourself. Sheer ability and knowledge is what you lack. You need a big grinder to go around the edges to take the old one off, Just grind until a line shows up and the inner edge of the skin releases. You are probably gonna need a smaller die grinder with a cutting wheel to grind out the smaller spot welds. take another die grinder with a stripping wheel on it once you get the skin off, and clean off all the old panel bond off the door frame. Scuff the back side of your new door skin. Put some new panel bond on the surface of your door skin where the door skin meets and make sure to cover all the metal. Put some seam sealer on the points on the frame where the skin touches the intrusion beam. Just glob it up on the old spots. Put your skin on the door frame, and then starts the fun part. turn the door over on your fender stand(do you even have any of these?) and then get your hammer and dolly and start to hammer it on. go around it at least 3 times, being very firm with the flat dolly on outside of the skin. If you don't have it firm then you'll beat the shit out of the skin and frame. don't try to beat it on the first pass. Then once you get it on and beat on all the way put the door back on the car and make sure it fits, have some vise grips holding on the top, if it welds there, if it beats on too, then get to town beating it on too. Get some paint paddles and wedge them and move the skin around while it is closed on the car, then, since you probably don't have a heat lamp, like a big one. Just leave the car sitting overnight. The next day, get 80 grit on a sander and sand the front of your door skin down. If you have dented it or warped it you will need to put some filler on it. Turn the door over and wipe seam sealer all pretty along the line of the skin. Then once it all dries prime as necessary, then get to painting.
Think you have what it takes to do it. I did one tuesday, but I've done plenty. I work day in and out at a shop. If I were you I'd buy a door that isn't destroyed.

GL either way.