DirectMusic is a powerful system, and the price you pay for that power is learning a whole bunch of terms and concepts. The upside, however, is that you can choose the amount of complexity you want. Start simple, by creating dynamic music with only a few components—music that sounds almost exactly the same every time it's played. Then, slowly build both the music itself, and the code, in parallel, until you've got a good grip on how all of these pieces fit together.