It looks like you haven't defined your layout and cards yet. Your default card has no metadata, and it looks like you're editing a card with image on top. The big blank area is your empty text area, I believe. That preview area will start taking shape once you create cards and map them to the layout.
You need to change the type of card you're using. On the left side, click the card name ("Default Card"), and then change the card type on the right side. I think you're using "Image Top" and you want "Full Image."