Using a rototiller, dig up the ground to a depth of four inches. Clear away any roots or stones that were churned up in the process. With a rake, smooth the surface of the soil. Be sure to break up any large clods of dirt.
Fill a lawn roller with water and walk it back and forth across the soil to level it. If there are low spots, fill them in with dirt so the lawn is as even as possible. Then, with a lawn spreader, apply a starter fertilizer to the soil, 6 pounds per 1,000 feet.
Lay the sod like bricks, with the seams overlapping. Press down firmly on each strip of sod to ensure that it has good contact with the soil, and place the strips tightly together to make it easier for them to fuse into a solid expanse of grass. With a sharp knife, trim the sod to conform to the shape of walkways, flowerbeds and lawn ornaments. Once all the sod has been laid down, drain half the water from the lawn roller and run it over the new lawn. Then, using an automatic sprinkler, soak the lawn until it squishes when you step on it.