The R1 does not handle PPPoE very well so better to offload that job to your modem. The Vigor and Openreach will not do that. Instead look at the Netgear DM200. It’s only £35 and allows you to easily see the state of your line sync and noise. You can open the modem interface from the R1’s device screen. I had the Vigor but when I switched to the DM200 the line synced to a faster speed.
you will need a modem such as an openreach hauwei hg612 or a draytek vigor 130 and then a router such as the R1 or the new Nighthawk XR500 which is launched here in the UK next thursday!
Depending on your isp they will provide you with a modem/router but they are usually shite so it is always better to invest in your own equipment!
The modem connects to the phone socket and then the netduma connects to the modem. Depending on Zen's connection protocol which is usually PPPoE then you go to wan options in R1 and input the PPPoE login details and off ya go!
My ISP talktalk has auto identification so I just connect my R1 to my openreach modem and that is that.
Welcome to the forum and any help you need we will be happy to assist you with!