Put a level on top of the dryer and orient it horizontally. Read the level by looking at the middle bubble. If the bubble sits slightly to the right of center, start with the left side and vice versa.
Go to the bottom of the dryer and look for the locking nut at each leg. The nut sits on top of the leg just below the dryer body. To unlock it, tighten an adjustable wrench around the nut and twist it clockwise.
Adjust the wrench size so it fits the foot at the bottom of the leg you want to adjust.
Twist the foot clockwise to move the dryer up. If the leg is already about 1/2-inch up, twist the foot on the opposite leg counterclockwise to move the dryer down on that side. Use quarter turns and check the level on the dryer each time you twist. Once the bubble on the level is centered, secure the locking nut on each leg by twisting it counterclockwise until it feels tight.