Say, your goal and plan is: You want to learn Nmap!
Knowledge level: What is a port scanner? Need to know TCP/IP, IP address, ports and services -- example HTTP 80/tcp, TCP session setup
So a newcomer should get this sorted out first, otherwise they cannot understand what Nmap does, and output returned
Then when they want to run this tool, they need to have operating system -- luckily Nmap supports Mac, Windows, Linux, ...
My recommendation: create a virtual machine with Kali Linux BTW then ... what is a Virtual Machine?! And so it keeps on
I am hoping to create some list of resources that will not overload a newcomer, but help them learn the required technologies step by step, while having fun and being engaged in this.