Skeetendo

Can you please provide more details on your normal workflow? Are you editing the repo files via GitHub web interface only?
Using git (the CLI program), you'd create a branch this way:

git branch name-of-my-new-branch    # create your new branch
git checkout name-of-my-new-branch  # move to the branch you just created

Or, in a single command:

git checkout -b name-of-my-new-branch

See also docs for git-checkout(1) and git-branch(1), or the corresponding man-pages.