There are a few ways to find this screen in Firefox.
- Go to Firefox > Preferences.
- Click Extensions & Themes on the bottom left of the window.
- Click on the icon that looks like three horizontal lines in the top right of your browser.
- Click Add-ons.
- Press shift + cmd + A.
On the left-hand side, you can navigate between your installed extensions and plugins.
In the search bar, type the name of the plugin if you know it. If you don't know it, then try searching for what your desired plugin does.
For example, I might search for a "grammar checker."
A new tab will open in your browser with the results of your search.
- Scroll down to find an appropriate plugin or extension. (If you're unsure which to choose, it's probably a safe bet to choose one with many users.)
- Click the Firefox plugin you want.
On this next page, you'll be able to see more information about the plugin or extension to help you decide if it's right for you.
- Click + Add to Firefox.
The plugin or extension will now install in your Firefox browser and a small icon indicating this will appear there.