Take off the door panel. You'll find 3 screws. One in the armrest, one behind a plastic cover near the sideview mirror, and a torx screw underneath the door handle - just pry it up like you're opening the door and unscrew.
2. Use your long flathead screwdriver or other similar tool to carefully pry the plastic panel away from the door frame. Careful you don't break it. There are a bunch of plastic clips that attach it - you will break some of these so don't freak out. Worst case you can always order some replacements for cheap.