This is still a very common question asked with the most of newbies as how can they add or remove any plug in into Mozilla Firefox? Firefox being the most popular web browser and its wide range of available plug-ins such type of questions are quite reasonable.

For installing plug-ins or addons in version of Mozilla FireFox make sure the extension of the plug-in it should be *.xpi  , if so, simply drag the file holding right button of the mouse and drop it anywhere over open Mozilla FireFox window. This should prompt with an installer window prompting to install the selected plug in. Click on the Install Now button (With in the window you can also view the installed plug in list. ) And if your browser prompt for the restart. Restart it and your plug in will be installed.

Though, here you have installed it but what if, you want to remove it from the system go to Tools >Add on and there you can see the whole list. Click over any plugin from the list, then you will see the options disable or uninstall. Disable for temporarily disabling it while uninstall is to remove for forever.