2010 Toyota Matrix Owners Manual - Page 117

1-7. Safety information STEP 4 While pushing the child seat into the rear seat, allow the shoulder belt to retract until the child seat is securely in place. After the shoulder belt has retracted to a point where there is no slack in the belt, pull the belt to check that it cannot be extended. STEP 5 If the child restraint has a top tether strap, the top tether strap should be latched onto the top tether strap anchors. Place the booster seat on the seat facing the front of the vehicle.