Every notebook has its own deck. One notebook per subject gives you a deck for anatomy, one for French and one for statistics without any sorting. A #project in the line lets you filter inside a deck, for example by chapter.
The decks with the most cards due come first. "Show cards" lists every card with its box, where you can edit or delete it. "+ Card" adds one by hand, and "To the page" takes you from a card back to the page it came from.
Cards and progress are yours alone, also in a notebook someone shares with you.