Q: Apple tv and a secure wireless connection

That would require a browser, which the device doesn't have. You will need to contact someone through the IT dept

When your daughter contacts the IT Dept at her school, she will need to provide the MAC address. Settings, General, Network

Right above the Signal Strength bars you will see a set of letters and numbers.

That is a hardcoded specific address of the device which is unique to it. Each network device has such an address (your smart phone, network printer, modem, your laptop, ...)

If the school allows they will enter the MAC address into their list of allowed devices to bypass the login screen.