There are two wire clips at the bottom of the back seat that fit into the frame of the car. Lift UP on the bottom left and then lift UP on the bottom right. Now pull the seat away from the back window towards you. In this last step you should be in the car facing the rear window. In the worst case you will bend the bottom clips but you can easily straighten them by hand.
Well this one has been posted last year but just a heads up to the poster.I have one for my e92 which has been slayed by our door. However i haven't hesitate to thown up such thing because i know there are available seat covers and rear seats i could find on local junks. Plus, I don't know about the sedan version, but you can zip off part of the e92 version to the seats.