Firefox Add-ons Installation Guide
Installing Firefox Add-ons
Installing Firefox Add-ons is quite easy. Simply follow the steps below and in no time you'll be using your new extensions and themes.
Also see, Manually Install a Firefox Add-on.
Learn how to install a Firefox add-on from a downloaded extension or theme file.
First, go to the Firefox Add-ons site and select the extension or theme that you would like to install.
Click on the Add to Firefox button and the Software Installation window will appear after the add-on has been downloaded.
After a brief countdown (takes about 2 seconds), the Install Now button will be active.
Click on Install Now.
Some add-ons (restartless ones), do not require restarting Firefox after installation.
For those, a small popup will appear after installation displaying an option to open the Add-ons Manger to explore the new options of that add-on (if any are provided).
For other add-ons, when the installation has completed, select Restart Now.
Once Firefox restarts you will now be able to use your add-on.
Many add-ons provide new interface objects such as buttons and toolbars and different customization options. Be sure to click on the Options button (if it has been enabled) in the Firefox Add-ons Manager, and also go to View > Toolbars > Customize to see if a new toolbar or toolbar buttons have been added.