Put on a pair of garden or work gloves. Make sure your lawn mower is powered off. Roll it to a flat, hard surface like a sidewalk or garage floor.
Examine the slotted rim above each of your lawn mower’s front wheels. Count the total number of slots in the rim. Compare each rim to see which slot is filled with the notched lever attached to the top of your lawn mower’s front wheels.
Decide which slot you want each of your front wheels to lock in place to. Placing the notch in the front slots will lower the front of your lawn mower so that its blade is closer to the ground. Moving it to one of the rear slots will raise the mower blade off the ground, leaving you will taller grass.
Use a chalk pencil to place a small mark above the slots you want to place your wheel notches into.
Press the rim toward the body of the mower with one hand. Pull the notched lever away from the mower with your other hand. Slowly and firmly move the notched lever either toward the front or back until you align it with the marked slot. Let go over the lever so its notch falls into the marked slot. Repeat this step for the other wheel.