2014 Nissan Sentra Owner's Manual - Page 47

If the seating position does not have an adjustable head restraint/headrest and it is interfering with the proper child restraint fit, try another seating position or a different child restraint. WRS0800 LRS0671 Forward-facing rigid-mounted - step 2 3. The back of the child restraint should be secured against the vehicle seatback. If necessary, adjust or remove the head restraint/headrest to obtain the correct child restraint fit. If the head restraint/headrest is removed, store it in a secure place. Be sure to reinstall the head restraint/headrest when the child restraint is removed. See "Head restraints/headrests" in this section for head restraint/headrest adjustment information. Forward-facing - step 4 4. For child restraints that are equipped with webbing-mounted attachments, remove any additional slack from the anchor attachments. Press downward and rearward firmly in the center of the child restraint with your knee to compress the vehicle seat cushion and seatback while tightening the webbing of the anchor attachments. 5. Tighten the tether strap according to the manufacturer's instructions to remove any slack. 1-28 Safety-Seats, seat belts and supplemental restraint system