Guidelines for contribution

Here is the approach you can take when contributing

1. Fork the repository to your user account
2. Clone the forked repository on your desktop.
3. Add remotes: [origin] for your forked repository and [upstream] for this repository. This will help you push your changes to your forked repository, and also keep up-to-date with this repository. Note that [origin] will be already set. So you just need to set [upstream].
4. Create a branch from the master branch of your forked repo. Make sure that you keep your master up-to-date with [upstream] i.e. this repository. Check this link.
5. Contributions/changes should be made in your new branch. Better not to modify your master branch.
6. After making changes, publish and push the branch. Now the changes can be observed on your online forked repository. Check this link.
7. Finally, create a pull request to merge your branch with this repository.

Git cheat sheet here.