I can’t figure out how to use this at all. How do you create a gallery?

I have used this plugin for years, but haven’t edited any photos in a long time, and this new version is totally baffling. I see no way to create a gallery in the plugin, nor to create a shortcode. I tried creating a gallery using WP’s built-in gallery creator, but there was no effect. I found shortcodes in documentation, but where are the id numbers coming from? I see no id’s on my pictures. I tried entering the shortcode [gallery type="rgg" ids="1"] but it has no effect. What, where, how do I assign id’s to photos or galleries? I just can’t figure this out and the documentation explains nothing. Can someone please help???