You can build a gallery with a lightbox and navigation arrows using the standard Wordpress Add a Gallery functionality and "Jetpack by WordPress.com" plugin:
In order to create a simple classic gallery please check the screenshots below:
Please go to your page/post VamTam Beaver Builder > Basic Modules > Text Editor > and insert a gallery by clicking the standard Wordpress button Add Media:
(You can also edit an existing gallery, if you edit the imported demo content)
You can watch the video guide Using a Media Library: Video Guides for Beginners
The "Jetpack by WordPress.com" plugin adds some gallery types and a carousel functionality:
You won't be able to see these types if the plugin isn't activated.
"Jetpack by WordPress.com" plugin comes bundled in the theme's required plugins. You can activate it in Appearance > Install Plugins. Here you can read more about this plugin: https://wordpress.org/plugins/jetpack/
If you don't have a Wordpress.com account and you don't need one, you still can use the Jetpack plugin - simply activate the Unplug Jetpack plugin in Appearance > Install Plugins
Here you can read more about this plugin: https://wordpress.org/plugins/unplug-jetpack/
Next go to Dashboard > Jetpack > Settings > Writing > Media > activate the options below:
There are some more options in Settings > Media > Image Gallery Carousel > tick the "Display all your gallery pictures in a cool mosaic" option. Change any settings you need. You can do it at later stage as well.