Setting up a Google Hangout is not obvious, here are the steps I take to create one.

1. Create the Hangout On Air

Go to https://plus.google.com/hangouts/onair, and click ‘Create Hangout On Air’.

2. Configure the Hangout

Set the title, description, start and duration. I also invite the relevant people/circles.

You should see your hangout in a list here: https://plus.google.com/events

You’re all set.

3. Start the Hangout

15 minutes or so before the start, go and find the Hangout page. If you’re running the Hangout, you must press the Start button, simply joining it will not give you the ability to start the broadcast.

4. Invite Guests

When starting the Hangout, you have the opportunity to add guests. I believe these people are then able to join in on the conversation.

5. Publish Links

When you’ve started the hangout, you then have an extra link which people can use to join as guests. I usually publish this in gitter/twitter so any other interested parties can join in.

6. Broadcast

When you’re ready to start, press the Start Broadcast button, and viewers will be able to watch your live stream. The video will automatically be saved to YouTube when you’re done.