Cadillac 1994 DeVille Owners Literature page 64

Securing a Child Restraint in a Rear Outside Position
You'll be using the lap-shoulder belt. See the earlier section about the top
strap if the child restraint has one.
1. Put the restraint
on the seat. Follow the instructions for the child
restraint.
2. Secure the child in the child restraint as the instructions say.
3. Pick up the latch plate, and run the lap and shoulder portions
of
the
vehicle's safety belt through or around the restraint. The child
restraint instructions will show you how. Tilt the latch plate to adjust
the belt if needed.
If the shoulder belt goes in front of the child's face or neck, put it
behind the child restraint.