1. Swipe through to find the card that has the Intro that you would like to create or delete the Intro to: 
2. Select the card to open the menu until you see "Intros": 
3. Select "Intro" from the menu bar, you may need to scroll down: 
4. If you want to create an Intro, then select the Green plus sign: 
5. If you want to delete a card intro swipe left to open the option to delete: 