Noteful Plus
I already have a Noteful account

On your smartphone, go to Settings (look for the gear icon in the lower lefthand corner of your homescreen).  Click on "My Account", and then click on "Subscribe to Noteful Plus."  Enter your code when prompted.

 

OR -

 

When you see a prompt in the app to check out Noteful Plus, click on it and enter your code.

 

You're likely to see the prompt at the end of a lesson, or if you run out of hearts.