Setting up Sophos XG Home in router mode

Hello, I have replaced my EE router with a TPLink AC2800, but keeping the EE router as a backup.

I want to setup a Sophos XG firewall at home in router mode and have put the TP-Link in bridge mode.

Do I need to put the VLAN into both the TP-Link and the Sophos box or just one of them?

Do i need to enter the broadband IP address or the default gateway into the preferred IP?

Thanks