1. Visit myaccount.google.com and sign in with your TSS credentials.
2. Click on 'Data & Personalization" in the left-hand menu.
3. Click on 'Transfer your content':
4. Enter a Destination account. This needs to be a personal Google Account that will accept the transfer of your data. Once you've entered the account name, click the 'Send Code' button to verify that you do control the destination account.
5. Open your personal Google account; you'll receive a message with a link to get the code:
The confirmation code will look something like this:
6. Enter the code back on the transfer screen for your school account.
7. Select the content that you want to transfer; when you're ready, click 'Start Transfer':
All of the selected content will be copied and moved to the new account. Note that this process does not remove any content (documents, emails, etc) from the school account.