Disconnect the electricity to the disposal's receptacle or junction box from the circuit breaker or fuse box.
Use groove joint pliers to loosen the nuts connecting the vertical sink drain pipe, the P-trap beneath it, and the horizontal pipe attached to the P-trap. Drain the trap into a bucket, then remove the trap and drain pipe.
Remove the nut that connects the sink flange to the sink with the pliers. Push up on the sink flange to remove it. Scrape off any plumber's putty adhering to the sink with a putty knife.
Lay a 1/2-inch bead of fresh plumber's putty around the drain opening and press the KitchenAid Quick Mounting System flange firmly through the opening. Wipe off the excess putty.
Slip the Quick Mounting System fiber gasket, backup flange and mounting ring over the flange from beneath the sink. Slide the snap ring into place on the flange. Tighten the three mounting ring screws with a screwdriver to secure the assembly.
Route the power cable through the access hole on the bottom of the disposal. Unscrew and remove the electrical cover plate from the bottom of the disposal and pull out the disposal wires and power cable wires.
Twist together the white wire from the disposal with the white wire from the power cable and secure them with a wire nut. Join the black wires in the same way. Connect the ground wire from the power cable to the disposal's ground screw. Replace the cover plate. Make the same connections with the wires in the junction box, or plug the cable into the outlet.
Align the three mounting tabs on the disposal with the slots in the mounting ring. Turn the mounting ring until all the tabs lock into place.
Clamp the KitchenAid drain tube into the disposal's tailpipe with the kit's hose clip. Reconnect the P-trap and tighten the fittings with the pliers.
Restore the power from circuit breaker or fuse box.