Git and GitHub are not the same thing. Git is an open source version control tool, GitHub is a company that hosts Git repositories in the web and provides a web interface to interact with repos they host.
Use git config with the --global option to configure a user name, email address, editor, and other preferences once per machine.
Files can be stored in a project’s working directory (which users see), the staging area (where the next commit is being built up) and the local repository (where commits are permanently recorded).
git add puts files in the staging area.
git commit saves the staged content as a new commit in the local repository.
Write a commit message that accurately describes your changes.