The answer to 'how does sod work' is that sod is pre-grown grass that is cut into rolls or squares and then transplanted onto a prepared soil surface. This allows for an instant lawn that can be established much faster than growing grass from seed. Sod is made up of the grass blades, roots, and a small amount of soil that holds the root system together.
To install sod, the soil must first be properly prepared by removing any weeds or debris, tilling the soil, and leveling the surface. The sod rolls or squares are then laid in a staggered pattern, with the edges tightly butted together. After installation, the sod must be watered regularly to help the roots establish in the new soil and prevent it from drying out.