Beginner Question

I am hoping for a little instruction. I don’t know how to get started. I understand you go to Tools shortcodes to get started but there is nothing there. “Add New” does nothing so I am pretty much at a stand still. Can someone give me some basic instruction on how to proceed? Please and thank you!

https://wordpress.org/plugins/shortbus/