How is Zenmap/Nmap Used in the Document Process?

In my Network TIA+ class we were discussing the document process and our teacher had us use Zenmap to learn more about it. I know that Zenmap is the GUI for Nmap and that you can target specific domains or IP address with a group of commands, and that an intense scan is an aggressive scan. But thats it.

I am trying to understand how you use Zenmap or Nmap for documentation and what you have to do in order to properly document your network.