I am teacher and I would like to make a NAS so as my students could long in and watch or download documenters, films or study material. Which is the cheapest model of WD NAS appropriate for this purpose?
I will let others inform you about a NAS, although there is another way to view excellent documentaries. See this link https://curiositystream.com/ Free trial available, I have an account which I enjoy very much. With just an iPad and Chromecast device on a TV you can view them on the big screen.