If you want to go further with this interaction, and allow only one card to open at one time, you can add more actions which reset all the other cards as one is opened.
1. Go to the 'image' actions for your first card. Set up the following action:
2. Add another action like the above for every other flipcard, so for this image you will end up with a reset action for every other card.... like in my example here....
3. Now you've added your reset actions to your first flipcard, do the same for your others. So, if you have 6 flipcards in total, each image will have 5 reset actions.
Test it! Once you've finished that, test it in learner view. Make sure you save your screen and also reset the screen state before you begin to test. If you spot any parts not working, go back to your actions and make sure you have added the right settings.