GMC 1997 Safari Owner's Manual page 56

6. With the other side of the harness, pull the shoulder
part of the harness out in a single motion and place
the harness over the child's shoulder.
If
the belt stops
before the latch plate reaches the buckle, let the belt
go back all the way and start again.
7. Push the latch plate into the buckle until it clicks.
4.
Select only one side of the harness. In a single motion,
pull the shoulder part of the harness out, and place the
harness over the child's shoulder. If the belt stops
before the latch plate reaches the buckle, let the belt
go back a l l the way and start again.
5. Push the latch plate (B) into the buckle until it clicks.
Be sure the buckle is free of any foreign objects that
may prevent you from securing the latch plates. If
you can't secure a latch plate, see your GM dealer
for service before using the child restraint.
8. Pull up on both latch plates to make sure they
are secure.