To add a title to your Wish List, hover over the little heart on the cover. Click on the heart and it will turn RED and the title will be added to your Wish List. It will remain red until you remove it from your list.
Your Wish List is empty. To add titles to your Wish List, simply click on the heart that appears near the upper right corner of the cover of the book you wish to add. The heart will turn purple as you hover over it and then turn red once you've added it to your Wish List.