Chevrolet 2006 Express Van Owner's Manual page 14

4. Push the pin with the black cap marked "R" down
until it is in the retaining clip.
1-8
5. Push the pin with the gray cap marked "L" down
until it is in the retaining clip.
6. If the vehicle has a floor mat, put the flap back to
its original position.
7. Repeat this procedure for the other seat base.
8. Connect the quick-release latch plates for the
lap-shoulder belts by inserting the latch plates
into the buckles attached at the outboard positions
of the bench seat. Do not twist the belt.
9. Check that all locking pins are locked into place
before operating the vehicle.