Heres how to use it.
Press on Start Broadcast.
It will upload your presentation to be shared.
This can take a while depending on how big your file is.
You will then be given a window with the link to your broadcast.
You will also see options to copy the link or to send it through mail.
Your viewers will just have to punch the link you sent them (via mail or IM).
The web app will open and they will see the presentation just as you are navigating through it.
They will also have an option to watch it in Full Screen View.
After you finish to present, your viewers will see a black slide telling them the broadcast is over.