Ip networking from Linux to dsl

Hello! I am a ccna but I don't know how to get 'ip route' trying to get an att/Arris nvg215 is set to WiFi off/bridge mode (I think).

Ip route get? Via? Onlink? [ " Update: sudo ip route add default via 192.168.1.215 onlink nexthop x.y.132.1 " yields 'error nexthop gateway does not match RTA_GATEWAY']

I want to route packets to the internet over bridged Arris box.

The pfsense box is supposed to be behind the Arris.

IP addresses:

Hp eth:192.168.1.215

Att wan:X.y.134.73:

Att lan: x.y.132.1

Arris webconfig:192.168.1.254

Arris box claims webconfig(think) is 192.168.1.214

Thx in advance