How to Use Emacs as a Git Client
emacs can be used as a git client using the magit package.
How to commit files using magit
After installing magit, navigate to a git controlled folder (I use M-x dired) and run M-x magit status. This will bring up the status of the current repository. From here you can use the arrow keys to select unstaged files and press s to stage them.
After you have selected all the files you wish to stage press c to commit. This will bring up the commit menu where you can select additional options. Press c again and begin to enter the commit message. Once you have press C-c C-c to finish the commit. Then on the status page select the unmerged changes into origin and press p to push the changes to your upstream origin (by pressing p again or one of the other presented options.)