Here are the basic steps -
Step 1 - find where the transformer is plugged into the wall of the grill. follow the plug to the square transformer part
Step 2 - unscrew the opposite wire from the old transformer
Step 3 - screw this wire into the new transformer
Step 4 - unplug the old tranformer and completely remove it
Step 5 - Make sure that the new transformer is plugged into the the wire leading the grill.
Step 6 - Plug the new transformer into the power plug located on your island that you identified in step 1