Date Today for Firefox

Firefox has made managing extensions (and finding where the h*** to write a review of an extension) difficult to virtually impossible for years. Their user interface for what should be an "everyday task" is beyond badly designed. That said, I usually manage to muddle through getting an add-on---sorry, "extension"....(or is it "add-on"?...Mozilla can't even decide on one effing name for the same entity)...to work. BUT add-on makers often share equal blame in making even getting a newly installed extension going onerous. This would be one of those. I just don't get this....like, at all. I install the extension, I set the various options...and nothing. For the extension to work, apparently there needs to be its icon in the toolbar. Nada. There simply IS NO ICON for this extension anywhere---not in the toolbar, not in the "hidden icons", nowhere. The second major problem, (though it's solved by the extension not even starting in the first place) is the basic design of this. My understanding from the description is that there would be a small clock/ day/ date icon in the toolbar. What I see in the descriptions is a big, mondo sized clock covering the upper right ~10 square centimetres of your current webpage?!? OR you might have to "call it up" every time you want to see it(?). That is NOT efficient or convenient. If, by some chance, I have completely misunderstood the instructions (and the raison d'être) for this add-on, then...sorry--not sorry. Given Firefox's aforementioned abysmal design of their extensions/ add-ons installation and management interface, add-on developers should make better instructions!