The answer to 'how to install grass' is to prepare the soil, lay sod or seed, and properly water and maintain the new lawn. First, clear the area of any existing vegetation, rocks, or debris. Till the soil to a depth of 4-6 inches, then level and smooth the surface. Apply a starter fertilizer to provide nutrients for the new grass. Next, lay sod pieces tightly together or spread grass seed evenly over the prepared soil. Water thoroughly, keeping the soil moist but not saturated. Mow the new grass when it reaches 3-4 inches tall, and continue watering regularly for the first 4-6 weeks until the roots are established.
Proper installation and ongoing maintenance are key to establishing a healthy, lush lawn. For larger areas or complex projects, it's best to consult a professional landscaper who can ensure the job is done right.