Sara's computer couldn't find computers on the network. Box popped up asking if I wanted to make the network I am on a private network, or turn on network discovery on public networks. I selected "make this network a private network."
Whether a network is considered "private", "work", or "public" is entirely up to the individual computer connecting to it, i.e., there is nothing inherent in the network making it private or public. Private, Work, and Public are each like a set of saved settings, defining how your computer should act when it connects to networks at home, or a network at work, or a network at a public place, e.g., the library, Starbucks, etc.
Network discovery is a setting that is automatically enabled for private networks and disabled for public networks. When enabled, it allows you to view all the computers that are connected to that network, and the files which they are sharing. When it is disabled, you cannot see who else is connected to the network, so if you want to share files, you will need to use a more complicated process in which you need to know the exact name of the computer you want to share with. Fortunately, I don't see us ever needing to learn how to do this!
