Pontiac Montana SV6 2008 Owner's Manual page 64

In Canada, the law requires that forward-facing child
restraints have a top tether, and that the tether be
attached.
If your child restraint does not have the LATCH system,
you will be using the safety belt to secure the child
restraint in this position. Be sure to follow the instructions
that came with the child restraint. Secure the child in the
child restraint when and as the instructions say.
If you need to install more than one child restraint in the
rear seat, be sure to read Where to Put the Restraint
on page 1-50.
1. Put the child restraint on the seat.
2. 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.
1-60
3. Push the latch plate into the buckle until it clicks.
Make sure the release button is positioned so you
would be able to unbuckle the safety belt quickly
if necessary.