Shortcodes disappeared

I’m new to WP. I’m constructing my first site.
I could click on the “Insert Fusion Shortcode” icon that appears in the visual tab of edit page screen and I would get a whole lot of different shortcodes offered. Now they have all disappeared. I switched to Tempera theme but they are still gone. Why have they gone and how do I get them back?
The first theme I tried and failed to use was Avada, – a Themeforest theme, but it confused me completely. My switch to Tempera was an excellent move as I am slowly working it all out much more easily than I did with Avada.
Does Tempera have a web page where the shortcodes are to be found along with notes on customising them? That might be as good or even better than getting the shortcodes back in my edit pages.