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If this an NBN compatible router for NBN Fibre to the Premises (FTTP) service, all you need to do is configure the following settings:
Username: <Your TPG username>
Password: <Your TPG Account Password>
Protocol / Encapsulation / Connection Type: PPPoE
Should you need assistance in accessing the router's settings, you may refer to this user manual we have found in Google.
AC3200 Tri-Band WiFi Router