Doesn't it just pull out? You should have to unscrew and remove some of the surrounding interior pieces but then i think it just pulls out. Not too familiar but thats what i think.
Fold the seat down. The piece on the floor, nearest the trap door, has screws holding it down. You should see the heads portruding through the carpet. Once that piece is off you will see the bolts that hold the seat back to the floor. Unbolt those and lift the whole flip down portion out. The seat bottom is pulled out by pushing in at the front of the seat bottom and lifting up at the same time.
Dave
Fold the seat down. The piece on the floor, nearest the trap door, has screws holding it down. You should see the heads portruding through the carpet. Once that piece is off you will see the bolts that hold the seat back to the floor. Unbolt those and lift the whole flip down portion out. The seat bottom is pulled out by pushing in at the front of the seat bottom and lifting up at the same time.
Dave