On the Digital Bookshelf section of your account, your item should show a "Click to Reveal", option on the cover of the item.

Once you reveal the item, please click "access".

The code may appear for you to copy OR after clicking access, a small popup box may appear in the top right-hand corner. It will state, "This item contains an access code. Click here to reveal."

Then you may copy your code for redemption on the publisher's site.