Good morning rayadams,
Thanks for your message and for being a part of the TPG community.
There are a few things you need to do prior to your TPG NBN connection happens:
1 - You need to give your current provider 30 days notice you want to cancel the service but be careful that your timings are correct to avoid a lengthy period without a connection.
2 - If you are going to keep your current telephone number you need to tell TPG, this process can take some time and at present due to Covid-19 restrictions it is taking longer. You may want to keep your current connection active until everything on the TPG connection (including the telephone) is working correctly.
3 - Prior to cancelling your current provider you need to migrate your data (email and contacts) across to another service such as Gmail or Outlook. If you have trouble ask you current provider for assistance.
4 - Make sure you have the correct modem/router for your NBN connection if you intend to use your own. TPG will send you the correct modem if you request it.
I hope that helps, good luck