Using D7000v2 router with Google WiFi

Not sure if this is the right place but I have a D7000 router and Google Wifi mesh kit and I want to take advantage of the USB ports for connecting some storage but in its out of the box configuration I can't see the D7000 when I'm connected to the mesh wifi. I've seen various articles about bridge mode but the entry under Advanced Setup for bridge mode doesn't exist as described on the support page.

Any ideas what I need to do?