First, take a putty knife and slide it down into the trim that surrounds the inside handle from the top (top will always refer to what would be up if tailgate was closed). This will have to be done the full width of handle and when you slide putty knife down into handle, do it a 45 degree angle. You will hear and see the tabs that retain it turn loose.

Next, take your fingers and roll the bottom edge of panel away from tailgate. You will see/feel/hear the retainer buttons turn loose. There are four equally spaced across bottom edge.

Last, pull the bottom edge away from tailgate a few inches and bump the panel straight up. Now it should be off.

The upper retainer clips will remain in tailgate panel(or should) and will have to be twisted to remove and then palced back into the four slots in tailgate so that when you go back together you will bump panel onto those clips instead of sliding panel back down tailgate. The other installation steps are obvious.