I'm Miles from the Social Care team at Shopify. Great to hear you've subscribed to our annual plan for the carrier calculated shipping rates. In order for you to activate this service, you'll need to chat with a Shopify Support Advisor who will be able to help out and get everything added for you.
To contact our support team, first head to https://help.shopify.com/en/questions and log into your store. Once you've logged in, you'll be prompted to ask about a topic. Doing this will present you with links to relevant documentation on our Help Center, but there will also be an option to contact us directly if you require further help. Clicking on this button at the bottom will then present you with the different support options available.
If you don't yet have a Shopify store or are unable to login, you can choose the "Continue without logging in" option at the start and continue through the same process.
If you get stuck, or have any questions at all, please let me know.