Gently pull up on the shoulder straps to tighten the lap section of the restraint harness. Click the chest clip pieces together and position the chest clip at armpit level. Slowly pull the adjuster strap to snugly adjust the restraint harness onto the child.
Check that the harness restraint is snug on the thighs and at the shoulders. You should not be able to pinch any harness material at the shoulders.