Can I install my Ring device without an existing door bell?
Yes you can! That is what I did with my Ring Pro. I used the Ring Pro, Ring Chime, and Ring Plug-in Power Adapter. Works great. I did need to get the power cord from the power adapter to the Ring Pro, but in my case that was not a problem.
I have one on my garage that has no doorbell and doens’t need one. I just use it as a camera.