After the installation process is complete, you need to enable the browser tool in order to use it:
Google Chrome and other Chromium-based browsers: type chrome://extensions in the address bar and check the Enable box next to the toolbar.
Firefox: press Shift+Ctrl+A (or open Tools → Add-ons). Press Enable next to the Smiley Bar for Facebook toolbar. If you can't find the toolbar in the Extensions tab, switch to the Plugins tab and look there.
Opera 12.x and older: press Ctrl+Shift+E (or press the Opera button → Extensions → Manage extensions) to open the Extensions menu. Press Enable next to the Smiley Bar for Facebook toolbar.
Internet Explorer: open Tools → Manage Add-ons. Select the Smiley Bar for Facebook toolbar and press Enable.