Do you have inside your home both an NBN-NCD and the TPG-Modem?
You will need to unplug all devices plugged into phones sockets, and use just 1x socket to connect the supplied equipment.
Here is a guide to show you how to setup your equipment.
You need to do some of the install yourself.
You will need to UNPLUG ALL existing phones/modems, and setup the new NCD + MODEM to the socket.
Pay attention to the 4x blue lights on the NCD once completed.
You may check the setup guide that we've created for NBN-FTTC here.