[LAU] Reference or HOWTO?

Is there a reference or HOWTO on how all of the various audio parts work together in Linux? I've looked around, and most are horribly out of date, and don't cover it all anyway. My goal is to get everything I need on Linux to replace my Sonar 3.1 setup, and it looks like the programs are available. I just can't get everything to work, and part of the problem is that I don't understand Linux audio very well yet. I need to understand how alsa relates to jackd, what is 'oss,' and why is that the only option available in Audacity to me that works, and why when I run jackd, some of my other programs no longer have a sound output available at all. Any help, or pointers to the information, would be greatly appreciated.