Nice idea, but what am I missing? It click on "Create New Note" and...nothing.

This the link (page) I used to add Page Memo to Firefox 57.01.
https://addons.mozilla.org/en-US/firefox/addon/page-memo/
I'm not sure this is what is needed, but it's all I have,

12-4-17 It's working! I don't have the slightest idea of what happened, but Page Note is putting notes on the pages. Looks good so far. It's a add-on that I've spent a long time looking for. Good work!