Question for people who have used Anki's flashcard app on an ipad

I downloaded the app called AnkiApp on my ipad air 2.

I downloaded a deck within the app.

I clicked the home button in the app (bottom left) and then went to one of my decks, which said it has 25 cards* on the left.

On the right, the app said something like Click Review to see cards.

When I clicked review, the app says that the deck has no cards despite *

Have you used AnkiApp before? What would be your advice for the above?