No internet at all!! And it's NOT required.
You need an internet connection to set up Apple TV, but not to use it. Obviously, it won't be able to access any on-line content when off-line. And it doesn't gracefully support storing content locally, so you'd need a network to access content.
What I am doing is peer-to-peer AirPlay to stream from my iPad/iPhone to the Apple TV.
Apple TV's use Bluetooth for discovery, and a point-to-point WiFi connection for data, no network is required.
I am NOT "entry level" here.
But this is all a mute point. The peer-to-peer is working fine, and it mirrors the iPad and iPhone correctly, EXCEPT the movies that are downloaded.
Again, this works on ALL the other TV's except this one.
The ONLY question I have for this support group is what causes the "This video is in a format that can't be streamed to this TV." As everything else mirrors fine. yes...without the unneeded internet,