Hi, moved into a new house, looking to extend wifi signal using Google Wifi, but hitting problems.  Apologies for terminology, I have no idea what I am talking about!

We have vodafone cable internet, with the standard modem they provide for this currently and the ultra hub.  The wifi signal with this set up doesn't cover the whole house, so purchase google wifi with 3 wifi points.  Followed the instructions (I think!) and disconnected the ultra hub, replacing it with first of the google wifi points.  The google wifi point for some reason would not connect to the internet.  After looking for advice, it was suggested I reconnect the ultra hub to the modem, and then connect the first of the google wifi points to the ultrahub using the ethernet cable.  This time it did connect to the internet, and I quite happily connected the other two wifi points which each were able to connect to the internet.

So far, so good.  Except not.  When trying to connect other devices to the internet through the new wireless network, they just refused.  Amazon Echo would not connect, and a Samsung TV would not connect to the internet through the new wireless network.

I've tried to read around - looks like I may have double NAT issues.

I guess the real problem is that the google wifi doesn't find the internet when connected directly to the modem.  I am not sure if there is some kind of setting on the modem that I need to change, and I am not sure how I can access the modem settings.  Or I am just wondering if there is some kind of incompatibility between cable broadband modems and google wifi.  It seems the ultra hub does not have a bridging mode, although I can't find much in the way of recent information on the ultra hub on the vodafone website at least.

Any help appreciated!