Air Parrot 2 is a Chrome extension found in the Chrome Web Store.

https://support.uscsd.k12.pa.us/kb/article/121-install-web-store-apps/

Open the AirParrot App

Make sure "Mirror Desktop" is selected, then enter the classroom Apple TV name.  NOTE: You MUST type in the "fully qualified" Apple TV name, which is the Apple TV name followed by ".uscsd.k12.pa.us." 

For example: bo-atv-123.uscsd.k12.pa.us

Click inside of the box to indicate what you'd like to share.  Then click "Share"

Enter the AirPlay password which is displayed on the Apple TV.  Then click "Connect."

While you are mirroring you will see a message indicating that mirroring is active.

To Disconnect, click the "Disconnect" button next to the currently active Apple TV name.