How do I properly adjust the mower cutting height?

Grasp the lift lever, press the plunger with your thumb, and move the lever to the desired position. The cutting height range is approximately 1-1/2 to 4 inches, measured from the ground to the blade tip with the engine not running. The average lawn should be cut to approximately 2-1/2 inches during cool season and over 3 inches during hot months. (Page 11-12)