The Mini Collections is active during the weekends only. You can collect chests to complete the unlocked locations when the Mini Collections is active. During the first weekend, only two locations are unlocked for collecting the required cards to complete the locations. During the second weekend, you'll have all the locations opened and can collect the remaining cards to complete a location. Once you complete all the available locations, you'll be able to claim the Grand Prize of 80,000,000 coins!

All the unclaimed Chests and Stars get reset at the end of each week's cycle, but the location's progress gets saved.