To use DisplayNote Broadcast you have to register for a free account. Once you've registered you can then just click the broadcast button to start broadcasting. A six digit code will be generated for you to share with your students. Students receive the broadcast by going to the DisplayNote Broadcast site and entering the six digit code generated by your broadcast.
Watch this short video to see my demonstration of how DisplayNote Broadcast works on a teacher's computer and on a student's iPad.Applications for Education
DisplayNote Broadcast is the type of tool that is great for getting all of your students to look at the same thing on your computer at the same time. I found this to be particularly useful when giving coding demonstrations to students as they could see things in more detail than just looking up at a projector screen.