Hello, Dear Customer!

Please, read the manual about how to use Unyson Page Builder you may download it here:

https://drive.google.com/file/d/1GmC2CFXsx_vuRufzgEG0NISgFPTVsG22/view 

It will help you to perform many changes with content on your current website.

Also, please read the following article on how to create the gallery on your website:

https://www.wpbeginner.com/beginners-guide/how-to-create-an-image-gallery-in-wordpress/

Best Regards!