How to save a README.md file for Github?

Hello! This is my first time, so please forgive me if I make some mistakes. This is also my first time using Atom, I just want to know how do I save a file? I plan on using Atom for Github.
Thanks in advance!

Wow, nobody is replying, this forum is dead.

Wow, still no reply?

REALLY???
10 unclear

Wow, this forum is doing a really bad job at helping people. It has been almost 2 months and I still haven’t got a reply.

See here …