How do I start using Facebook video calling?I do not see it in the chat sidebar options.Also I do not see the option on the profile pages of my friends.  
Activate (Start) Facebook Video Calling
facebook
Login to Facebook.Go here: https://www.facebook.com/videocallingClick on the Get Started button.Click on a contact from your friends list.You will see a new button in the upper right corner of the chat window.Depending on your OS, you might need/not need to install something.Installation Flows for Each Browser and OS  To make installation as easy as possible, we specifically customized the installation flow for each OS and browser combination. For instance, on Mac browsers with Java enabled, the installer is hosted entirely within the browser so that no additional clicks are required. We use a small bootstrap EXE in Windows browsers to minimize the initial download time and to manage installation permissions as seamlessly as possible.From here: https://www.facebook.com/notes/philip-su/building-video-calling/10150229123673920