The phone should be plugged into the socket on the back marked "phone 1"
and the light on the modem labeled "phone" should be on.
If its not the modem may be faulty, or your account may not be set up correctly.
You might have to contact TPG too arrange for a tech to visit you.
Try turning everything (phone, modem and connection box) of for 1 minute.
Turn evrything on, and leave it all for 10 minutes before attempting anything else.