New houses come with a minimal amount of landscaping. The builder sometimes just includes a few bushes and a tree or two in the landscaping packages. That leaves an expanse of dirt, especially in the backyard. The quickest way to convert that dirt to a usable yard is by planting sod. What was a dust bowl or mud puddle when it rains becomes an expanse of lovely green grass within a day or two.
Till or dig the area for the lawn. You might be tempted to skip this step if the yard is flat and level. Don't. Soil preparation is important to the success of the lawn. Add nitrogen fertilizer at half the amount the package suggests. New roots are susceptible to fertilizer burn. Till or dig the area again and rake level.
Water the lawn area until the soil is wet to a depth of 6 inches. Review the lawn for any high, dry areas or puddles. Level out those areas. Wait a day or so for the lawn area to dry out a bit so it's not muddy.
Starting at one end of the lawn area, lay out strips of sod until you reach the other end of the lawn area. Lay the second set of strips so the junctures between the first and second set of strips are staggered. Cut the strips if necessary. Think of a block wall fence. The blocks are not stacked so each one is directly on top of the other with the seams between the blocks in a straight line. They are staggered so the second block is set on the juncture of the two blocks below it.
Butt up the strips to each other as closely as possible. There shouldn't be any visible dirt between them. Walk on the junctures between each strip so it makes contact with the soil. The edges of the strip are most prone to dying.
Water the area so it's soaked. The weight of the water will help the sod make contact with the soil below it. Keep the sod wet for the first three days. Taper off watering to once every other day, then every third day and finally until you reach the normal watering schedule for your geographic area. Dry, hot weather means additional watering.