Our main project is EasyRPG Player, the RPG Maker 2000/2003 games interpreter. It’s written in C++ and uses several libraries, like SDL for window management and basic keyboard and audio output.
The first step is to build the software yourself. You should try to get source code from upstream master repository and build it. The wiki development pages shows how to build EasyRPG Player.
How to get source code and required tools and steps for building: easy-rpg.org/wiki/development
In a nutshell, we use Git repositories to work with source code, so you should take a look about how Git works if you are not familiar with it. We are using the GitHub repository services and have “upstream” repositories there, and fork this repository with own versions then request a pull to be merged in upstream, so we are not using upstream directly for pushing commits. You can learn more at help.github.com/
Git features code branches and they are good for specific feature development. There are multiple branches in development and they are listed in this tree: github.com/EasyRPG/Player/network
e.g.: There is a mruby branch refactoring all the non-core system to support ruby bindings, a SDL2 branch to support SDL2 window/audio output, etc.
We coordinate our work via IRC chat. If you have any questions you can talk directly with us at irc.freenode.net channel #easyrpg, or IRC web interface from webchat.freenode.net/?channels=easyrpg