Obtain a replacement cooktop from the manufacturer or from a home improvement supply store. Wear work gloves to replace your broken glass cooktop.
Unplug your KitchenAid oven from the outlet and slide it away from the wall to give yourself room to work.
Open the oven door and look underneath the top of the oven for the two screws that hold the glass cooktop in place.
Use a screwdriver to remove the screws. Set the screws aside in a safe location so you can find them when you are ready to secure the new cooktop. Gently lift the front of the glass cooktop and disconnect the cooktop wiring for the burners from the oven's wiring. Hold the cooktop with one hand and pull the cooktop's plug from the oven wiring at the back of the unit with your other hand.
Lift the broken cooktop and place it out of the way. Slide the new cooktop into place. Lift the front of the glass cooktop so you can reach the wiring. Reconnect the new cooktop to the oven's wiring.
Replace the screws and close the oven door. Plug in the oven and slide it back into its normal position. Turn on the burners to test that the wiring is connected properly.