Start by prying up the small plastic cover at the base of the rear headrest. Remove the two 13mm bolts on both headrests and remove the headrests.
Remove the rear upper garnish moldings by prying he small access cover(sedan only) and remove the screw inside the hole. Then pull on the panel to release the clips.
Open the trunk, and release the rear seat backs, and fold them down. There are four 10mm bolts next the the latches of the seat backs, remove them. Pull the seat frame forward and remove the push pins from the rear window shelf panel.
The next step can be tricky without removing the seats, but it can be done without ruining any parts.
Remove the rear window shelf panel by pulling it forward. There are four 7mm bolts holding the rear speakers in.