Gallery: how to customize

Hi,

Made a gallery with the Page Builder. But I can only make 3 columns.
https://www.strongzzz.nl/index.php/historie/hengelo/hengelo-1945
(at the bottom of the page)
Also, I don't see the title of the photo. So two questions:

1. How can I change the number of columns?
2. How do I display the total of the photo?
   Thank you very much for your answers!

Gr. Marc