Let the audience say a card, then you do some magic, you swipe the screen and try to find that card, finally let the audience flip the card over, wow, its exactly the same card as he selected.
This is one of the possible scenarios, and you can do lots of other magic with the help of this app. Download the app and the instruction page will tell you how to play the trick, just after some practice, you will be a true magician! Enjoy it with your friends!
p.s. Long press on the screen can lead you to the instruction page, you can learn how to play the trick there!