A deck with Anki is like a set of flash cards.

The idea with spaced repetition is you go through the flash cards, and reschedule them for later depending on how well you feel you know it. If you feel you know something really well, it will schedule it days or weeks away, if you don't know something, you will start seeing it more often. There app automatically schedules based on how you score (1-5 based on how much you know it) each card after you answer it.