When you start a Challenge level, you will be presented with 3 different tasks. Picking one will open the machine.

As you play, the progress towards completing the task will be tracked across the bottom of the screen. When you complete the task, you will receive Coins immediately and be able to move onto the next level.

You can only work on one task at a time, but also you only need to complete one task to earn the Challenge reward and move on. We recommend focusing on the tasks that are suited to your playstyle and the machine.