Oldsmobile 2003 Silhouette Owner's Manual page 68

You'll be using the lap-shoulder belt. See the earlier
part about the top strap if the child restraint has one.
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.
1.
2.
Put the restraint on the seat.
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.
In the third row, tilt the latch plate to adjust the belt
if needed.
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