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 > Tilled Galleries > 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.
In case that you can't build the beautiful mosaic gallery like the demo one, please check the troubleshooting instructions below.
First, go to Settings > Media and check if the Tilled Galleries > "Display all your gallery pictures in a cool mosaic" option is enabled.
If this option is missing, proceed with re-activating it in Jetpack > Settings > Debug
Next, locate the "Access the full list of Jetpack modules available on your site."
Activate the "Tiled Galleries" from the "Photos and Videos" category:
Finally, go back to Settings > Media and enable Tilled Galleries > "Display all your gallery pictures in a cool mosaic" option.