When I'm in bebuilder and I click on "export section" nothing happens. How do I save that section as a predefined one to use on another page?
When you click on the export section option, you can put this section on the same page or open another page and put it there.
If you will use this section on a couple of pages, you can use it as a Global Section.
If you just want to have this display but the content will differ on different pages, you can set it as a Page template.