When you install an add-on it creates an icon for it in your add-on icon area (to the right of the address bar). If you have many add-ons installed there probably isn't room in your browser bar, so click on the puzzle piece icon to reveal hidden add-ons.

This isn't something I as an add-on developer have control over. But it is standard behavior with every single add-on you install - if there isn't room it'll be hidden in this dropdown list. I suppose I could create instructions for this, though it isn't unique to my add-on at all. This add-on's icon is a red square with a white "B" in it, by the way.

Also, "us add-on guys" spend a lot of time creating FREE software used by thousands of people every day, with only the occasional "thanks" in return. This isn't meant as a complaint, because it is rewarding by itself, but a little patience and politeness go a long way 🙂