yeah I was messing around with it and fuck....put it in a V and damn it was crazy. You have the level on the right and the values are pretty wide on each band...adding or cutting. It can get wacky quick.
A good way to start is with everything on the eq centered; play into a clean amp using the most neutral setting (e.g., middle pickup selector) to get an even sound; then move each slider on the eq to max cut and max boost while just playing a full chord (E, G) that uses all 6-strings. Reset that slider to zero and move on to the next band.
Repeat the process until you hear what each slider does to your sound.
Then, zero the eq settings again, and play with a normal guitar tone you use, then adjust the EQ; start with maybe cutting the low and high; then boost/cut your low mid, mid, high mid; etc. don't go to extremes on the boost/cut.
Once you get used to the frequency bands in the graphic eq, then experiment with the parametric eq.
With a PEQ you can usually set a frequency center, then the bandwidth (wide to narrow) around that center; then boost and cut; experiment with different frequency centers and widths; one at a time.
I view GEQ like a set of butter knives, one for each band; they work but they're general purpose; the PEQ is more like a razor sharp scalpel and lets you really get as narrow and close to the frequencies you want to boost or cut.
How many bands does your PEQ have, 3? If so, maybe start with a low cut and high cut with two, and use the remaining band to find the narrowest frequency; e.g., start with a 1K or 2K center frequency, and wide band, then narrow it; move the center frequency, start wide then narrow; each time boosting and cutting.
just takes time to experiment and listen to find what works for you.