Crystal Quest is a time-limited event with multiple steps, each having a specific crystal goal and reward. You collect crystals by solving untangled twists while playing a level. 

When you reach the crystal goal for a step, you get a reward and move to the next step. If you complete all steps in the event, you win the Grand Prize. The more steps you complete, the more rewards you earn.

To participate in Crystal Quest, you need to reach Level 26. You must beat levels to collect crystals, but if you lose or quit a level, the crystals you got won't be counted towards the event.