I have recently purchase ring doorbell 3. I have set it up and connected it over my existing doorbell with the relevant wires going to the relevant connectors on the back of the ring doorbell 3. I am having trouble with my existing doorbell. I understood that I could connect my existing doorbell to the ring doorbell 3. The existing doorbell I have I believe is mechanical. The existing bell makes a ‘ringing sound’ and the sound is dependent on how long you press it. I have attached some pictures of the doorbell and the transformer, hopefully this will give a better understanding of what we have. Could you please review and tell me if you can where I am going wrong on getting my existing doorbell to work with my ring doorbell 3. Thanks All