Missions are a feature that will allow you to win prizes through classic games and daily challenges. They are made of four tasks that you'll have to complete in order to win the prizes. You'll be able to access them in the "Missions" box in the home screen.
Once you access, you'll learn what you have to do to complete them. As soon as you finish the first task, the next one will become available and so on until you finish the mission. You will have 96 hours to complete the four tasks.
All of these tasks have to be completed in classic games, so you will have to start new games or continue playing your ongoing games.
Once you complete them, you'll have to access the "Missions" box to claim your prizes.
Keep in mind that this feature will be active from Monday to Friday and you will find it in the main screen.