Full Screen in Popup Showing Tiny

Hello,

I want to use the flipbook in a pop out but when I select “full screen” and add the shortcode, the thumbnails are tiny. I tried increasing the size in “Book Properties” “Sheet Properties” etc., but it only makes them smaller. Can you give me some guidance on how to fix?

Click on the “Track Record” icon or link to see:
https://odyssey2018.calicowebsites.com/

The page I need help with: [log in to see the link]