First of all, thank you for contributing, you are awesome!
Here are a few rules to follow in order to ease code reviews, and discussions before maintainers accept and merge your work.
You MUST follow the PSR-1 and PSR-2. If you don't know about any of them, you should really read the recommendations. Can't wait? Use the PHP-CS-Fixer tool.
You MUST run the test suite (run composer update, and then execute composer run phpunit).
You MUST write (or update) unit tests.
You SHOULD write documentation.
Please, write commit messages that make sense, and rebase your branch before submitting your Pull Request.
Also, while creating your Pull Request on GitHub, you MUST write a description which gives the context and/or explains why you are creating it.
Thank you!