To activate a new book into your existing account, follow these steps:
Log in to your account
Go to the Music Studio section
Click on the Activate Book 1, 2 or 3 tab on the left
You will then be asked to enter your Essential Elements Interactive Activation Code. Enter the code, then press the Submit button.
If you are having issues finding the Activation Code in your book, it can be found using the example below:
After your new book has been activated, you can change between the books in the Music Studio and clicking on the Songlist tab on the left. From there, you can use the Change Book dropdown menu towards the top of that page: