when you log into SE account management do the following:

1. Look at the list on the right at the bottom is "Select Service" go ahead and click on it

2. Next be given the option for FFXI or XIV services go ahead and select XI

3. you should now be at a page where it lists your active accounts and towards the top a blue button that says Add a Service account As misleading as this title is this is where you want to go. go ahead and click on it

4. you are now taken to a recognizable page where one can input registration codes go ahead and do so now after u do so it will ask which account to apply the code to*

5. Your account now has access to all the add ons and upon your next game log in screen it will be represented by all the icons to teh right of the character select screen being lit up. If you are logged in while th code is applied it will most certainly require a logout and login to take effect.

*(if you have multiple POL IDs make sure you choose the correct account to apply the codes to)

Hope that helps