Don't reverse the disassembly order for reassembly???
Agree, the service manual could definitely use better instructions if p 20-37 (20-38 in my 1995 SM) is all we've got to go on. I found for taking the panels off, it seemed easier to remove the left & right rear trim panels first. Start with the 2 lower clips, then work up to the 2 upper clips, and then slide the each panel down and out. You can then work your fingers or a plastic spatula tool around the clips that hold the rear upper trim panel pop it out.
To put it back together though, I find it's difficult to get the left & right trim panels oriented to their clips and also to the 4 metal flaps on the rear upper trim panel, if the upper trim is installed first. I find you can visually line up the left & right trim panel clips if the upper trim panel is not yet installed. Once the left and right rear trim panels are installed, hook those upper trim panel metal tabs behind the left, right, & center rear trim panels and then feel with your fingers to line up the upper clips on the rear upper trim panel.