Attach the garden hose to the water aeration tool. Turn the water on and adjust the flow so that steady but fairly gentle jets of water come from the tines of the tool.
Press the tines into the lawn and step on the crossbar with your foot. Don't push too hard, or the tool may clog. Wiggle the handle of the tool back and forth a bit as you press down if necessary. Let the water do most of the work.
Insert the tines fully. Water deeply for two to five minutes, depending on water flow and soil permeability. Ensure that the area is moist, but not marshy.
Move to a new location 6 to 12 inches away. Repeat the procedure. Work in a grid pattern until the desired area is aerated.