On mine, there are holes on the sides of the seatbacks. There is a piece that is attached there, to extend the sides of the seatback. So that the back of the seats extend all the way to the sides of the troop.
Remove those pieces, and the seatbacks will lay down flat, either direction. Lay the seatbacks, back, and you create a "bed".
There are attachment points on the front/base of the seats as well.
Attach the pieces that you took off the sides, to the fronts of the seats there, and you extend the "bed" all the way to the backs of the fronts seats.