I've worked with DMX for years, what makes it hard to understand is the technical descriptions of DMX makes it sound much more complicated than it actually is.

The below site should help:
http://www.ubasics.com/adam/electronics/dmx512.shtml

As was mentioned above its all about learning how DMX functions. Once you understand that the rest is pretty straight forward. We can't write the code for you but we can provide you resources; which in this case are located elsewhere on the forum.