Workflow: small fixes
Open Source is awesome because a community works together to improve the project. Even small contributions add up, and small contributions can be submitted completely on the GitHub website.
If you do not have forked the project yet, please do so now. What this does is simply to make a copy of the project in your GitHub user space, allowing you to edit. Do not worry about disk space, the "copy" is not a true copy, but will share most data with the original repository.
GitHub allows you to edit files in your repositories. Just navigate to the file you want to modify and click on the pen icon; This will let you edit the file in the web browser.
To finalize your change, scroll to the bottom part, provide a short (<70 characters) description of your change (it is a good idea to replace the Update <file> message with something substantially more informative, such as Fix dead link to XYZ or Grammar fix), and provide background information in the bigger text box (it is a good idea to describe the motivation for the change unless it is obvious).
To get your changes into the main project, simply go back to the top-level page of your repository and click the Pull Request link. This will notify the maintainers that there is a contribution, and if everything is fine, merge the changes. Congratulations, now you are a contributor!