Achim is right, although, if I remember right,it is easier if you first lift up on the seat cushion at its front edge and remove it. It has a spring bracket that is snapped over a rod welded to the floor "beam" between the seat cushion and the foot well behind the third seat foot well. Otherwise, the seat cushion restricts the movement of the lower part of the seat back and keeps the stud from being pulled straight out of the hole in the wall of the rear compartment. A small point, but important and leads to frustration if you don't really know how the Kinder Seat assembles in the car.
Tom Kizer