3D FlipBook - How to query FlipBooks within a category?

Hi! I´m using the pro version of 3D FlipBook. I need a list of books within a category defined in a custom post. I am using the ACF plugin to select the category to display in the list of books in these custom posts, but the Categories from 3D FlipBook does not show up among the visible categories. I have also tried using the post object selector in ACF (assuming you are familiar with that plugin) to manually select each book in the list. But all content EXCEPT the books are available there. (This is not an ACF issue, I´m just trying to explain that the books behave differently than other content types)

How can I query the books within a category and get thumbnail, title and the slug? (I know about the short code option, but I need a customised list)

Hope you can help me out. Thanks!