Oldsmobile 1998 Silhouette Owner's Manual page 97

5. Pull the rest of the shoulder belt all the way out of
the retractor to set the lock.
6.
7.
To tighten the belt, feed the shoulder belt back into th
retractor while you push down on the child restraint.
You may find
it
helpful to use your knee to push down
on the child restraint as you tighten the belt.
Push and pull the child restraint in different
directions to be sure it is secure.
To remove the child restraint, just unbuckle the vehicle's
safety belt and let it go back all the way. The safety belt
will move freely again and be ready to work for an adult
or larger child passenger.