According to a Google support document, you can set up the new Hangouts On Air by creating either a "Quick event" or a "Custom event" using YouTube Live's Creator Studio tool. You can either go live immediately or schedule a YouTube Live broadcast for later. As with the version on Google+, you can have the Hangout be public, unlisted or private to just a select group of invited guests. Unfortunately, Hangout On Air apps like Q&A, Showcase and Applause aren't currently available on YouTube Live, though they might be in the future.

The move to YouTube is yet another sign that the company is changing Google+. Last year, it moved Google Photos to its own product and even completely redesigned Google+ to be more of a community site than a social network. It also retired the G+ account as a requirement to register for services like Google Play Games and YouTube.