A thin prybar with a 90 degree end works well for removing the panel with the door closed. something like this:
As others have said, start by removing the small plastic cover by the pull strap and then remove the bolt behind that.
Next, move to the lower corners and free them. Work towards the center, and then up each side. Hook the prybar behind the panel and pull towards yourself.
Once you're that far, lower the rear window and then lift upwards to remove the panel.
Raise the window to within an inch of the top (this will come in later)
Next you'll have to remove the middle access panel. Disconnect the electrical harness (3 plugs) and then remove all the bolts and then pull it off. There's snaps behind that, so you can work around the edges again if need be (these snaps are a different design and harder to break)
Once you have the panel off you should be able to see the rear door handle. Follow the rods to the driver's side. There's your latch. Actuate the latch by pushing the rod towards the latch (I think. If that doesn't work try the other direction)
Now you can get the door open. congratulate yourself.
Now comes the part where you have to figure out what's wrong. That's on you. If you need to get the door handle off You'll need to unbolt the window regulator (4 bolts) and then you can move the entire regulator/window assembly around to get clearance to the various attachments. The handle comes off with the bezel if you have to go that far, but you probably wont.
If you remove the rod from the handle, pay attention to which direction the bracket goes. it will bolt on in either direction, but will only work in one.
Once you get it sorted out, then re-install the window regulator. This is where you thank yourself for leaving the window down a crack as it will be much easier to position the regulator in line with the bolt holes.
Installation, as they say, is the reverse of removal. Be sure to test the door before you put all the access panels and trim back on!