Hi Acecryz,
That's a pretty broad question and depending on your experience and/or knowledge of ROS, the answer widely varies.
If you're new to ROS. It would probably be a good idea to start with learning a little bit about ROS, for instance by looking at the ROS Tutorials. The first tutorial deals with setting up your environment and a workspace, which you will need to compile and run the nodes.
For a more thorough introduction a book might be easier, several are listed at the ROS wiki over here. This includes both free and paid books.
As a last piece of advice, you have a better chance of getting a satisfactorily answer if your question is a little more specific, and also include what you already know and have tried yourself.
Good luck!
UPDATE : the guy who made the node gave the entire catwin_ws file but all I want is the node that makes motor controls work without the MEGA 2560.