Not sure if this is the correct place to also ask a question on shortcodes, if not please say so. I have activated the shortcode.zip file in plugins and for the life of me cannot see where to find the ‘insert shortcode’ button on the page being edited. I have also added all the plugins your suggested in your article.
I actually moved this topic to the Seasonal Pro category as I should move the other one too, but for the shortcodes relating to Seasonal Pro, there are only a small list of them so there is no insert button for it. However, it’s more of a copy & paste method. Not sure if you seen the tutorial for it, but it gives you the shortcodes to use: