Do I need transformer and can I protect 2 properties?

Hello, I have two questions. Can I use my one Ring subscription account to have Ring security at two properties with different addresses & wifi? (I.e. my home and my dad’s home) This is my first time using Ring. For the product “Ring Video Doorbell Pro with the Plug-In Adaptor” , do I need a transformer? The product video makes it look like I can just feed the plugin adapter cable through a brick wall hole and attach it to the doorbell pro on the other side of the wall. (I have no other doorbell or wiring) Thank you