Rated 1 out of 5 stars

installed version 8 does not work, restarted firefox several times . checked add manager and it is listed. however icon does not appear

This review is for a previous version of the add-on (0.8). 

Icon is on the statusbar.
By default, the add-on bar (a.k.a. status bar) may be hidden. So you need to turn it on by clicking View->Toolbars->Add-on Bar. Click Alt key to see the menu where View menu is located.