Chevrolet Uplander Owner's Manual page 76

Storing the Built-In Child Restraint
Always properly store the built-in child restraint before
using the vehicle's lap-shoulder belt.
1. Move both latch plates and both sides of the
shoulder harness clip to the bottom of the
harness straps.
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2. Fold the child restraint cushion and leg rest up
into the seatback.
3. Press the child restraint cushion firmly into the
seatback.