Always place rear-facing safety seats in the reclined position at a 30 to 40 degree angle. Keep the harness snug, and at or below the shoulders.
Never place a rear-facing child seat in front of an airbag,
Most babies will outgrow an infant seat (designed for babies 20-22 pounds) before age 1. Change to a convertible seat with a higher rear facing weight limit.

Your child is ready for an adult seat belt when they can sit with their back against the vehicle seat edge without slouching, and feet touching the floor

Children 4 feet 9 inches or more can correctly fit in a lap/shoulder belt.

Convertible or combination seat 1 to 4 years old

Place forward- facing in the upright position
Move the harness straps to the proper reinforced slots
Keep the harness snug and at or above the shoulders. Check the manufacture’s instructions for exact positioning
Some types of child seats can be used as a booster seat when the harness is removed

A child who is both under age 8 and shorter than 4 feet 9 inches is required to be fastened in a child safety seat or booster seat that meets federal safety standards. Under this law, a child cannot use a seatbelt alone until they are age 8 or 4 feet 9 inches tall – whichever comes first. It is recommended to keep a child in a booster seat based on their height, rather than their age.

Booster are necessary for a child who has outgrown the convertible or combination seat. Booster seats keep the lap belt positioned properly aaround a child’s hips and the shoulder belt in the correct position.
Some booster come with a high back, others come without a back, but both must be used with a lap and shoulder belt.
Boosters without a back may only be used in vehicles with a head rest.
If a vehicle is equipped with only a lap belt, use a tethered harness or check with an auto dealership to have shoulder belts installed.