Pontiac 1996 Grand Prix Owner's Manual page 63

4. Put the belt's special latch plate into the vehicle's
safety belt buckle.
5. You can make the belt longer by tilting the buckle
and pulling it along the belt.
5. Put the restraint on the seat. Follow the instructions
for the child restraint.
7. Secure the child in the child restraint as the
instructions say.
8. Run the belt through or around the child restraint.
The child restraint instructions will show you how.