Problem installing Pro Power Kit (for Ring Doorbell Pro)

I just bought a Ring Doorbell Pro (to replace existing hardwired doorbell), and the first thing in the instructions is install the Pro Power Kit, which is a little device that goes inside the existing doorbell box, and has two wires: one is to be attached to the "Transformer" terminal, the other to the "Front". Sounds simple. It's purpose is to provide the proper power level to operate the doorbell. I removed the decorative cover on my inside doorbell chime and there are TWO transformer terminals, Transformer A and Transformer B, instead of just one like is in the instructions. I used both in turn, and had the same issue with each one. The problem is that **the doorbell starts chiming when I hook up the Power Kit, and just keeps on chiming as long as the Power Kit is hooked up.** Note that I did not turn the power off at the breaker box because it is so poorly labeled that I have no idea which breaker the doorbell chime is on. Not knowing anything else to do, I scheduled a professional installation through Amazon, but thought I'd check here and see if anybody could suggest a solution. If so, I can cancel the Amazon order.