If you haven't filed your taxes for the current or previous tax year, you can't register for a CRA account. You'll either have to file a 2023 or 2024 return and sign up once you've gotten your Notice of Assessment, or wait until next February when you can file your 2025 return.

You can login to TurboTax Canada Online 2023 here: https://ww1.2023.ca.turbotaxonline.intuit.com/

You can login to TurboTax Canada Online 2024 here: https://ww1.2024.ca.turbotaxonline.intuit.com/