I can do my best.
To get at the connections behind the driver's seat, there are two panels that must come off and a third one that makes accessing it easier, but not necessary.
The first panel that has to come off is panel 2 "Rear Upper Trim Panel" in that diagram. It is the one that lays horizontal directly underneath the rear glass behind both seats. There are three clips holding it in, One on each side maybe 3 inches in from the exterior edge, and one in the center. In addition, there are metal guides along the bottom that hold it tight to the lower panels. To remove, gently pry up on the edge until you can get the clips to pop out. You may use a trim removal tool to ease with this process. Be careful not to crease the panel or break the pieces that hold the clips. If a clip ends up breaking, you can buy replacements at NAPA. Once all three clips are popped out, pull up on the panel and it will slide out.
The second panel is the square one directly behind the drivers backrest (Left Rear Trim Panel). This one has four clips that hold it in, one on each corner. Gently tug on the top ones until they pop, then the bottom.
The third panel does not have to come all the way off, but you do have to loosen a few screws. They are typical interior phillips head. Just remove them along the edge of the trim.
Once that is done, you can access the CD changer cable.