How do I use Apple TV Mirroring?

Important Note: As of March 2015, the tech department disabled the network protocol (called Bonjour) that is used with AirPlay. A workaround to this issue is forthcoming.
Apple TV mirroring is more commonly known as Airplay mirroring.  It's the method by which you can show your Mac, iPad, or iPhone screen wirelessly through an Apple TV to a projector or flat-panel TV. At the new middle-high school, Apple TV boxes are directly attached to Media Master on each projector. The only way to show what's on the Apple TV is to choose the Apple TV input on Media Master.  It cannot be accessed through the Epson projector remote.
Airplay mirroring is bandwidth intensive.  This means that it takes a lot to seamlessly transmit what's showing on your Mac, iPad, or iPhone wirelessly to the Apple TV.  We don't have enough experience with Airplay mirroring.  We are aware that in certain situations that Airplay mirroring is blurry or it freezes.  Please be patient as we work through learning the idiosyncrasies of Airplay mirroring.
There are a few steps to making Airplay mirroring work.  Please read this carefully.  You may already be aware of or have completed some of these steps. 
To access your Apple TV, first login to Media Master with your user name, room number, and password.
To use Airplay mirroring, you must first be connected to the "Duxbury" wireless network.  The list of Apple TVs will not appear on Duxbury2.
To wirelessly send your Mac, iPad, or iPhone to the Apple TV in your classroom, choose the Airplay button in the menu bar of the Mac or from the control center on your iOS device.
Windows computers can install third party software to Airplay mirror their computer screens through Apple TV.