This is an activity to be used after students have had some practice with the language. I would not use it to introduce the target language.
Cut out the cards and each student should get one.
Demonstrate with the JTE. ALT and JTE walk up to each other and say 'hello, how are you?' 'I'm good thanks, and you?' 'I'm great, thanks' and then one asks the question on their card. The other answers then asks the question on their card. Ideally you should demonstrate simple reactions to their answer such as 'nice' or 'cool' or 'Me too'. After that you exchange cards and make a new pair, have another conversation with your new card and then exchange cards again and continue to find new partners until time runs out.
As a level up after doing this for a few minutes demonstrate expanding the conversation beyond the cards with a question or two or a longer response.
Before the students start mingling its important to tell them they should try to speak English, they shouldn't just run around and they should not avoid people. If you do more than one round also encourage them to talk to new people.
If your class is too wild when it comes to mingler activities I'd skip this activity.