Though, you may need to download the video and audio plug-in before doing that. Also, if you need to start a new hangout session, then only press the button mentioning the name ‘Start a Hangout’. It will make your entry to the already going hangouts.
All you need to do this is just click on the hangout tool bar on the left side of your Google+ account. To start or join a Google Hangout on Mac is very simple and easy process.
Also check : Snapchat -Download for windows 8