Hummer 2007 H2 Owner's Manual page 23

To install the seat, do the following:
1. While holding the rear of the seat up, slide the
front wheels into the slots on the floor. The
front latches should lock into place. If the
latches do not lock, try tilting the rear of the
seat upward.
2. Once the latches are engaged, pull up on
the lever labeled 3 to allow the seat to drop
into place.
3. Pull up on the lever labeled 1 to return the
seatback to its upright position.
4. Push and pull on the seat to make sure it is
locked into place. The seatback cannot be
raised to the upright position unless the seat is
secured to the floor.
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