You mean you have downloaded Firefox? What is your specific question?

The OP is referring to the 600% sound extension. It looks like you control it with a toolbar icon.

https://addons.mozilla.org/firefox/addon/600-sound-volume-privacy/ https://addons.mozilla.org/firefox/addon/600-sound-volume/

Thanks! I did find access there in my tool bar. Too bad the ap doesn't work. Many reports on the page of others that found this ap does not work. It actually turned my sound off completely and I had to reload the page/video to get it to play.

You helped me, but the ap was not working.