This is from one of the manuals.

• 5. Place a level on the cabinet top and check if the washer is level from side to side and front to back.
• 6. If washer is not level, tilt washer back to access the front leveling legs. Loosen the locknuts and adjust legs by screwing into or out of washer base.
• 7. Once adjusted, tilt the washer forward on front legs and lower back down into position to set the rear self-leveling legs.
• 8. Washer must not rock. When washer is level and does not rock, tighten locknuts securely against bottom of washer base.
• If these locknuts are not tight, washer will not remain stationary during operation.
• Improper installation or flexing of weak floor will cause excessive vibration.
• Do not slide washer across floor once the leveling legs have been extended, as legs and base could become damaged.
• 9. Verify that unit does not rock.