Buy netgear nighthawk router setup

[Controlled_]

I'm a noob when I comes this, but I'm looking through this video https://www.youtube.com/watch?v=Oil-ZLP7ibw on how to set up the router and it's saying that I have to connect my modem up to it, but I don't have a modem, all I have is a BT router. Do I have to buy a modem or..? I'm a noob when it comes to this

 

[BK_123]

After a quick bit of research, the Nighthawk X6 is a router only which doesn't have a modem built-in meaning that you need to buy a seperate modem. I found this which should help Using your own router with BT Infinity « Ed Spencer's Blog.