Using GitHub and atmom

Hey, i ask for some assistance in using Atom with GitHub,

To make it clear, i don’t know GitHub very well, i use Linux though.

On GitHub, there is active repository, that means there are accepted pull requests from time to time,
i have a copy of this repository on my hard drive as well.
My Atom is conneted with Token to the GitHub.

  1. Is there update possiblity to download newest changes, through Atom from the GitHub?
  2. If i would change a file, and want to upload it, how to do it properly?

Thanks in advance for assistance!