When you click on the Share Screen option for the first time, a pop up will ask if you want to add the "Facebook Screen Sharing" extension. We tested it out and successfully installed it on Chrome. After that, a module will appear asking if you want to share your entire screen or if you just want to share a specific tab or a specific application. As TheNextWeb said, it's pretty basic -- you can't insert a video of yourself on the lower corners while you stream your screen, for instance. It doesn't produce the clearest videos either, but if you don't stream for a living anyway, the option looks good enough to use whenever you want to share with friends.

NEW! Facebook screen sharing option on FB Live via https://t.co/Luozcvmz9G (desktop / laptop) pic.twitter.com/1CN2nsaUrT — Matt Navarra ⭐️ (@MattNavarra) October 17, 2017