https://guides.github.com/activities/hello-world/
To create a new branch
Go to your new repository hello-world.
Click the drop down at the top of the file list that says branch: master.
Type a branch name, readme-edits, into the new branch text box.
Select the blue Create branch box or hit “Enter” on your keyboard.
Now you have two branches, master and readme-edits. They look exactly the same, but not for long! Next we’ll add our changes to the new branch.
Make a commit
On GitHub, saved changes are called commits.
Each commit has an associated commit message, which is a description explaining why a particular change was made. Thanks to these messages, you and others can read through commits and understand what you’ve done and why.