You know how to use them. But I usually ask my Ss to answer all parts on their own in silence. Then I collect the cards and shuffle then give them back to students randomly, then they have to speak about the student whose card they're given. You can also ask them not to mention the name and have the class guess who the person being described is. It makes them more confident to talk.
I've also put circles on top of each card to punch and make a booklet.