Tuleap Open ALM is a Libre and Open Source software forge crafted in PHP/MySQL. Development occurs in realtime on https://tuleap.net. Sources are available in a Git repository on Tuleap.net. You can find a mirror on GitHub.
Use case, screenshot & more on https://tuleap.org.
You should follow the installation guide and the user guide.
The tuleap-devel mailing list will be more than happy to help you to get the most of the software, don't be shy we are nice with new comers.
You can start looking at the Tuleap developer guide and of course you should subscribe tuleap-devel mailing list.