I have the JVC KDSH77 with the same 3-band quasi-parametric equalizer. Basically, here is what you need to know.
The eq is basically a flexible bass/treble control. Whereas most bass/treble controls are adjustible at a fixed frequency (usually 100Hz for bass and 8 or 10kHz for treble) you get to pick which frequency you want to center your adjustments at. The level adjustment should be self explanatory with an adjustment range of +/- 6 steps i think.
Now to explain "Q". Q is basically a measure of how wide a frequency range your adjustments will impact. The lower the "Q", the wider the frequency range that will be affected. The higher the "Q", the more focused and narrow your adjustments will be.
As for what settings are "right" for your particular application, only your ears can tell you that. Unless you have access to an RTA from Audio Control, Coustic, LinearX, etc., trial and error on your part is the only method you have. Take your time with it and treat it as an opportunity to learn (yes, I said "learn"!) about accoustics and equalization as well as what sounds good and not so good to you.