There are two main ways to get the grassy yard that you desire. Both will require a good amount of soil preparation. All the leaves and small branches need to be raked up and composted. Once you are down to bare ground you will need to till the soil, leveling and adding good bedding soil where the soil is not conducive to plant growth.
- Grass Seed
You can purchase bags of grass seed and a spreader device to cast the seed down over the prepared soil. Once the seed is down you cover the area with a mulch such as sawdust or other material specified for the purpose. The mulch layer holds dampness as you water the area, keeps the seed moist so that it will germinate and keeps it in place where you cast it.
- Rolled Grass Sod
Grass that is cut from the ground surface at a sod farm are formed into rolls and bundled onto pallets. You can purchase these and get them delivered to your lot. The sod is unrolled and placed on the prepared soil in an orderly manner starting at one side and working your way back to the other leaving a carpet of "instant" grass.
Both methods will require you to learn how to care for the seed/sod via watering and in some cases a moderate fertilization to get the grass to grow. The biggest challenges are hot sun that bakes the surfaces, excessive rain or flooding that can ruin either type of installation.
If the ground area is prone to having a lot of thistles, weeds and residual growth from old roots then it may be necessary to lay down a permeable yard fabric over the prepared surface before to inhibit that growth. If doing yard fabric it is typical that you would bring in top soil and spread a layer of that over the fabric so that the grass seed or sod have something to root into as it grows.