a) Hire a contractor.
b) DIY.
1. Ask a local sprinkler store to design heads & pipping placement patter, valve box, timer, and head sizing.
2. Coarse grade with a backhoe or bobcat with bucket.
3. Knock down high spots with shovel.
4. Final rough leveling the land with 4 prongs cultivator, and pick out or bury the large stones.
5. Top dress the land with 4-6" of topsoil.
6. Rough leveling the top dress and pick out large stones.
7. Pre-finish the top dress with garden rake (try to bury small stones as you rake so money and effort of remove and disposal).
8. Dig trench, rough-in sprinkler piping, install valve box (1/2" above finish top dress), wiring, timer (water test rough-in sprinkler), and fill drench (flag sprinkler heads position, and valves box/es).
9. Final finish with landscaping rake (bury small stones using similar method as step 7)
10. Install sprinkler heads (turn water on to blow out dirt & contaminate in pipping), test sprinkler heads and set sprinkler sweep coverage (heads 1/2" above finish top dress for sod, or 1/2" below or the same height as fishing top dress for seeding).
11. See below for sodding, or seeding.
11a. Roll out, cut sod to fit, start from the outer border, lay sod across,off-set the sod in brick like patter to minimize sod lines)
11b. Seed ground with seeder, or by hand evenly in 2 runs and crossover/overlap for even seeding. Use leaf rake and run parallel lines across the top dress & seeds to mix in the seed with the top soil, run lawn roller the surface to tamper the seed (prevent wind/water from wash away the seed, and birds from eating it). Water for 2-3 times per day at 10-15 min each (do not let the top surface dry out until at least after 2-3 times after first mowed) for 1-4 weeks of germination.
4 prongs cultivator
garden rake
leaf rake
lawn roller