1.  Remove all the seat upholstery screws on the original seat.

2.  Remove the seat upholstery off the cross frame.

3.  Remove the end caps on both sides of the cross frame.

4.  Slide the seat with the extension into the cross frame.  It may be easier if the extension is removed from the upholstery.

5.  Tap the extension all the way in until it is against the cross frame.

6.  Install all the seat upholstery screws into the cross frame.