Remember all the pink donuts you found in hidden object scenes? Once you've found twelve of them, you can open a Donut Box full of spectral binders!

You can claim a Donut Box inside the Shop. To find it, tap the Shop icon in the bottom right-hand corner of the main map screen, then tap the pink chest icon.

If you've collected twelve donuts, you'll be able to open a Donut Box by pressing the "Claim" button.