How do I adjust the harness straps and head support on the All One Car Seat?

Have your child lean forward slightly before adjusting. Squeeze the fed head adjustment handle on top of seat and pull head support up until it snaps into one of the 6 height positions (use bottom 3 positions for rear-facing, top 4 positions for forward-facing). To lower, squeeze the handle and push down. Check that it is securely snapped by pulling up on the head support.