Climb up a ladder and locate the air conditioner on the roof. Measure the length and width of the base of the air conditioner. Record the measurements and purchase four pads so one can sit under each corner of the air conditioning unit.
Turn off all power to the air conditioner from the inside of the house to make sure it is not running while the vibration pads are being installed. Locate all of the bolts and screws holding the air conditioner in place on the roof. They will likely be drilled straight into a concrete pad that is already installed.
Loosen all of the screws with a power drill and remove all the bolts with a socket wrench. Work from one side to the other until the air conditioner has been loosened from the concrete pad and can be lifted up. Tilt back slightly on the air conditioner and have a friend tip it back toward you to lift up the first corner.
Slide the first vibration pad under the corner of the unit and set it back down. Tilt up the second side and set the next pad under it. Repeat the process for each of the remaining sides until there is a vibration pad under each corner. Check to make sure they are centered under the air conditioner and are all perfectly even.
Tighten all of the screws and bolts back into place on the concrete pad. Verify that the air conditioner is stable on the roof and turn the unit back on to make sure it is not vibrating when in use.