In order to make a pull request you need to do the following steps:
- Fork a repository (to which you want to make a pull request). Just click the fork button the the repository page and you will have a separate github repository preceded with your github username.
- Clone the repository to your local machine. The Github software that you installed on your local machine can do this for you. Click the clone button beside the repository name.
- Make local changes/commits to the files
- sync the changes
- go to your github forked repository and click the "Compare & Review" green button besides the branch button. (The button has icon - no text)
- A new page will open showing your changes and then click the pull request link, that will send the request to the original owner of the repository you forked.
It took me a while to figure this, hope this will help someone.