Have someone ring the bell while you are next to Rover. If Rover keeps on barking, check out the paragraph on the bottom of the page. Do this in every training session. If Rover forgets, go back to the last step. After you get to the last step make sure Rover stops barking at the doorbell.
Further directions are below.
Hold up a piece of Rovers favorite doggy treat. Sometimes our dogs just like to see us suffer as we make the measly attempt to teach them a simple trick. Please only try these directions if the above directions did not work. For most dogs the above directions will be better and easier to teach then the one below. Another one you could try is tying Rover up rather short and bringing out his food.