if you do not have fold downs, you need to remove the lower seat cover by pulling up on it at the corners. To remove the rear upright portion, give it a good tug and it will pop out too. If it has never been removed there will be two bolts also holding it in place behind the seatbelt clip. Once the rear seat portions are out, remove the headrests (if equipped) and the pillar trim. Then undo the 4 retaining pins and the rear shelf slide out.
<span style='color:gray'><span style='font-family:Courier'>1995 e36 3 Series RIP
1999 e46 3 Series BURN IN HELL
2000 MR-S Roadster= Current</span></span>