Hi @valeriet1, welcome to TPG Community!
First, you have to make sure that the service under your name has been activated. You should get an email notification once the activation is complete. Next, you have to configure your modem with your TPG details. Here's how to setup the TP-LINK C1200 modem: How to set up TP-LINK C1200 modem
If you need further help, you can send us a private message with your details so we can look into your account and go from there.