General considerations

Only 10 people including the "cameraman" can be in the Hangout. These people MUST be identified ahead of time and need to provide their Google Account addresses to the meeting host/cameraman.
Participants MUST be in the hangout NO LATER THAN 15 minutes before the scheduled start time.
Viewers will view the hangout via the OpenMRS YouTube channel on YouTube.com, or on the Google+ Event page. They can provide feedback via comments on those pages.
If someone does not have a Google Account or is otherwise unable to join, it's possible to call out to a phone line IF AND ONLY IF the Hangout is NOT "On Air".

1 day (or more) before the hangout

Become the OpenMRS page identity on Google+.
Post a new event in the OpenMRS Contributors community on Google+: https://plus.google.com/b/111781005975931971145/communities/118053496152947717740
Use a neutral kind of theme image.
Title: "OpenMRS ______ Hangout"
Do not choose the advanced option for making this event a Hangout
1. (last we checked, it wasn't possible to make the associated hangout "on air", but this may change)
2. you will need to start the hangout as the infrastructure account right before the event starts
Be sure to set the correct start & end time based on the time zone displayed.
Provide a useful description.
1. also say "We will post a link for viewing this event as it starts."
Invite any other relevant people to the event that were not automatically invited (by being members of the Google+ community).

Log in to Google+ using the infrastructure account.
Contact the meeting host to make sure they are available to get the hangout set up.
Go to https://plus.google.com/hangouts and start a hangout and invite the meeting host. For the hangout Name, use the same title as the event earlier, e.g., "OpenMRS Foo Bar Sprint Kickoff". Be sure to click "Enable Hangouts On Air".
Check your camera, microphone, and sound settings, then click "Hang Out".
Click the "Embed" link next to the "Start Broadcast" button to copy the YouTube video URL.
Back in Google+, switch to the OpenMRS page profile then navigate to the Events tab and find the event. Under the "Actions" menu, choose "Edit event".
In the Edit event dialog, click the "Event options" dropdown menu and choose "Advanced", then "Show additional fields". In the "YouTube URL" field, paste the URL you copied in step 5. Save the event.
Finally, make a comment on the event that says something like "YouTube video for this Hangout for observers will be available at: http://youtu.be/xxxxxxx".
The meeting host should invite hangout participants appearing in the hangout.

Ensure the hangout participants are in the hangout and all their audio and video is works. The cameraman (logged in as the infrastructure account) will be able to preview the YouTube page video before the start of the event.
As appropriate, use the "Cameraman" Hangout app and disable your own image from being shown in the hangout.

Inform the participants you are starting the live stream, then click "Start Broadcast".
Monitor the YouTube page comments, and as applicable, the event comments and/or IRC, and pass questions or comments to the hangout group via the Group chat sidebar.
The sidebar chat is ONLY to be used as a back-channel communication. It is not viewable in the Hangout On Air so any questions there should be read back aloud by someone for the sake of viewers. Speak up!