Korea's college entrance exam day (Suneung)

Before the event starts, under Ready-made in Walls. It arrives on its own, with no app update, and leaves after the event.

Each broadcaster decides when its coverage starts. Until then its screen says the channel isn't live: reload it later, or put another channel on that screen.

A lineup of up to nine live channels picked by the Skywall team. It opens in one tap, and you can change any screen and save your own version under a name.

No. Every channel is a free live stream that the broadcaster publishes on YouTube, with its own ads. Skywall itself is a one-time purchase, with no subscription.

Yes. Connect your iPhone or iPad to the TV with a cable, or use Screen Mirroring to an Apple TV, then tap Use the TV. The wall moves to the big screen and your device becomes the remote.

One at a time, so the wall never turns into noise: tap a screen to hear it while the others keep playing in silence. Double tap a screen to fill the wall with it.