Locate the round opening in the top side of the lawn roller barrel, and remove the cap using the manufacturer's instructions. In most rollers, the cap turns counterclockwise to unscrew. Fill the barrel of the lawn roller half full of water using a garden hose. Replace the cap tightly.
Move the lawn roller to the end of the sod, and push it across the entire length of the sod using a slow, steady pace. When you reach the end of the strip of sod, turn the roller around in the opposite direction, and push it back across the sod.
Continue pushing the lawn roller back and forth over the sod, overlapping each strip by an inch until you have rolled over all of it.