Here's a rundown on how to set up a Google+ "Hangouts On Air" to broadcast your Roll20 game live to YouTube. When the Broadcast is finished, your session will be saved on your personal YouTube channel for people to watch afterwards.

Initial Setup

1. Have your Roll20 Game open either in another tab or new browser
2. Go to Google+ and create an account if you haven't already made one
3. Go to your personal Google+ homepage
4. Click on or mouse over the "Home" button on the left side of the site. It'll bring up a list of options, one of them being "Hangouts On Air" - Click this option
5. This will bring up all the Live Hangouts that are currently airing. On the upper right portion of the screen is a button called "Start A Hangout On Air" - Click on this button
6. This will then prompt you to add people into your Hangout. If you want to just test things out, you can go ahead and create the Hangout with just yourself in it. You will need to create a name for the Hangout to proceed regardless if guests are added to the Hangout or not. The Hangout Name is what the resulting YouTube video title will eventually become. You don't instantly start broadcasting just by making the Hangout itself. Click on "Start Hangout On Air" to start up the Hangout.

Hangouts On Air Basics

You'll be introduced to the Hangouts On Air UI. On the bottom is the "Film Strip" which is where everyone's webcam footage is displayed (*note, you don't HAVE to have/use a webcam in a Google+ Hangout. If you don't want to supply video, click on the crossed out camera icon on the upper right portion of the screen) On the left side of the Hangout UI is the App List. When you click on an App on this bar it will reveal itself somewhere on the UI.

For the most part, a Hangout On Air is very similar to a regular Google+ Hangout with a couple big exceptions. When you start up a Hangouts On Air, there'll be a red button on the very top of the interface that says, "Preparing Broadcast" followed by a percentage that will start to count up to 100%. When this percentage reaches 100% the button will change to, "Start Broadcast". Clicking on this will start transmitting the Live Broadcast to your personal YouTube channel, so don't click on that button until you're ready.

Next to the broadcast button is an Embed link. When you click on this it'll give you the direct URL for the resulting YouTube video this Hangout will start broadcasting to. It also gives you the HTML code to embed a link to said YouTube video. One of the extremely convenient things about Hangouts On Air is that people can watch and comment live on your Hangouts on Air directly from YouTube. They don't need to be in the Hangouts to watch and ask questions. Also, after the broadcast is finished, that video will be archived on your YouTube channel for other people to watch later.

Broadcasting a Game

Displaying Roll20

One of the things that Google will hopefully fix eventually is that a broadcast doesn't record third party Apps running in a Hangout. So if you're running the Roll20 App within Google Hangouts, the broadcast won't actually display it. The current workaround is to use the "Share Screen" App and then choose the tab or browser that is currently logged into your Roll20 Game.

Fielding Live Questions from YouTube

Anyone who's watching the resulting live YouTube broadcast can ask questions in the comments section of the YouTube video. You can keep track of these in Hangouts without having to scan YouTube. Hangouts has an App called "Hangout Toolbox" which can help you follow, queue and answer questions submitted from YouTube. (*Note: you might have to click on the ellipses(...) on the App bar to find the App.) The Toolbox displays on the right hand side of the interface. By default it should sit on the Comment Tracker tab. If it doesn't, click on the tab with the chat icon on it. Paste the URL of your YouTube video there and click on the add button to get the Toolbox to start tracking comments submitted to the YouTube Video. It's important to note that only the Hangout Creator can use and view this App.

Optimal Setup for Broadcasting

Because of the Screen Share workaround, you might want to figure out who's better off hosting the Hangout On Air. The GM might be better off as a guest to the Hangout rather than the Hangout Host, because they'll be hard pressed to keep an eye out on YouTube comments while screen sharing their Roll20 Game. As a guest, the GM can go about their business undisturbed and the Hangout Host can watch the questions and comments and pose them to the GM at their own pace. If you go this route, the Hangout Creator should click on the GM's filmstrip to force the broadcast feed to stay on the GM sharing their screen. Otherwise, the feed will bounce around to display whoever's currently speaking on their mic.

Another thing you can do is the GM can host the broadcast and have one of the Hangout guests sit on the YouTube broadcast and watch for questions that way. Like before, the presenter will want their filmstrip selected to keep the feed focused on their Roll20 screen share regardless of who's talking on the mic.

A third way is have one of the players screen share their Roll20 screen from another tab and then those watching on YouTube don't see the GM's view.