What are the smart downloads on Netflix?

What does it mean when they are on / off?

The download function is available on devices that meet the requirements listed below. It is not supported by computer browsers.

If you download something from Netflix series episodes to watch offline, you choose the episodes you want to have, right? I don't know if you've done this before.

If you have already watched these episodes, the smart download will download the next few episodes if you have Wi-Fi. So that you have it immediately next time.

So you can only watch 1 episode offline when it's on?

No. As many as you want. Depending on how many you downloaded beforehand.