Frank, this is kind of "learn by doing."
There are (or were, I haven't looked recently) some step-by-step instructions on Rational's online support. They walked you through setup of the i/o, verifying hookup with a loop back test, etc. They progressed on to using the software, making measurements and a little on interpreting the displayed results. Try to find these getting started tutorials.
A more difficult to answer question is "what will it do for me?" You're right, the software, measurement mic, training and incidentals comes in at around $1500-$2000. That's not cheap and you have good reason to question how much actual benefit you'll get for the investment. The quick answer is that if you don't need to align subs & tops, or mains and front fills or delay rings or under balcony fills; if you're not building crossover/DSP for a multi-way speaker system; you might not feel you're getting your money's worth.
OTOH, once you see how much time relationships govern everything we do in audio, the utility of these measurement tools becomes more obvious. Also throw in that a measurement system can show you things your brain doesn't process in a linear fashion...
Hang out with Jay. He'll show you how it's done. What use you can make of it, though, is up to you.