Electric Novice

Hi. I'm really sorry about this because I know it's going to be a silly question but I have an existing wired doorbell in a house that is about 20 years old.However, when I look at getting a wired Ring doorbell, the installation talks about a transformer and I have no idea whether I have one or not. All I can see is the wires where the old door bell is and the door chime is on the wall in the hall so where would the transformer sit?Given my lack of knowledge, do I need an electrician to fit it for me? I've looked at various guides and they all look simple enough apart from the bits about the tranformers.Thanks in advance :wink:I should maybe have added that I'm in the UK?