-VoIP will not work
-Set VLAN ID 2
-Connection type PPPoE
-Need your TPG username and password
Additionally, you can plug in TPG supplied modem to the NBN box and then plug your Orbi to the TPG supplied modem (any LAN port). You may want to disable WiFi on the TPG supplied modem and set your Orbi as the access point.
This may be helpful: https://www.wikihow.com/Connect-Two-Routers