How do I install the Evenflo Nurture car seat with the convenience base using a vehicle seat belt?

Place the base on a level vehicle seat and route the vehicle seat belt through the openings as shown in the manual (lap belt only for lap belts, or lap portion only for lap/shoulder belts). Pull the shoulder belt tightly to remove all slack from the lap portion while pushing down on the base with your full weight. Check that the base is secured and does not move more than 2.5 cm (1 in.) side-to-side or front to back. If using a lap/shoulder belt with an emergency locking retractor, you may need to install a locking clip. (Pages 25-26)