Hi @Kalpana . Note the default ip address to login to router and default wifi details on label on router.
If you are on BYO data only plan (no VOIP service), VLAN tagging is not used.
Do a factory reset first.
Login and select Basic.
DSL mode: VDSL if you are FTTB/FTTN. Or Ethernet WAN if you have an NBN box.
Connection type is PPPoE, your TPG username and password.