First, there are two pieces of plastic that just pop off. One is behind the door handle, the other is on the under side of the arm rest. Just shove a flat-head screwdriver into the notch in the plastic and pry them off. The arm rest is the toughest. It'll feel like you're going to break it, but it'll come off.
Once you have those off, there will be four screws you need to take off: two behind the door handle, and two deep inside the arm rest. There are two other ones on the arm rest that do not need to come off. Well, you could take those off if you want to make more work for yourself. But you really don't need to.
Now you can remove the panel, but not so easily. It's still held in by plastic clips every few inches around the sides and bottom. You can carefully use a flat-head screwdriver and pop those up as you go around. Or apparently, there's a tool made just for this. I didn't use either method. I just yanked really hard, starting on the hinged side of the door, where I could more easily get my hands behind the panel. If you try this, don't blame me if you break anything. I didn't, but that doesn't mean you won't.
Once you get the sides and bottom free, the top will need to slide up and over the lock. And once that's loose, you'll find the wire for the window still hanging on. Just squeeze that and pull it off and the whole door panel will be free.
I found that some of the white plastic clips stayed in the door after I pulled the panel off. You can see them in the picture. If that happens to you, pull them out by hand and slide them in the spots on the panel where they came out of. They'll need to be there when you put the panel back on.
And voila! The panel is off. Now you can go on to do whatever you needed to like, say, fix the door checker.