Question for those who have already started the card game:

You can acquire the rewards by turning over their respctive card.
After turning 5 cards of any type, you can turn over to a new sheet.

You can open up to 16 sheets.
The rewards will become more attractive and abundent which each sheet passed.
NOTE: Some sheets will be added in the second half of the event.

You can check out the items you can acquire in the "Rewards" tab.

You can also choose what sheet to play from the "Sheet" button.

That last line, does it mean that we can go back to previous sheets, or do we have to go forward, like the resets on gacha events?