The Jamin mastering application, which you can use as an Aux Send/Return, has two views of EQ: the graphical curve-based HDEQ, and a slider-based 30 band EQ. They are literally two different views of the same thing, so it's typical to use both views depending on what kind of adjustment you need to make and which one makes that adjustment easiest.

The practical theory behind EQ is simple enough; identify the frequency you wish to emphasize or supress, and then raise or lower its intensity in the equalizer. If you are unfamiliar with equalizers, you may have a difficult time at first being able to identify where in the spectrum of frequencies the sound lies. Put simply, the lower (bass) bands are on the left and the higher (treble) are on the right, with the mids (human voice and similarly pitched instruments) are in the middle.

For more precision, there is an old engineering trick that you can use in Jamin to identify where something you are hearing actually appears in the spectrum:

Less is more in EQ; rarely is there a time when huge increases or decreases of the existing frequencies are required. If you find yourself wanting to maximize the intensity of a frequency band then quite possibly you need to re-record to achieve the actual sound you were intending to capture.

The other view of the EQ in Jamin is the 30 band EQ tab, which displays the same information as the HDEQ interface, but uses sliders instead of graphical curves and nodes.

The same principles apply; the sliders provide a quicker way to boost or cut frequencies when you know exactly what needs to be done and don't want to have to draw curves and move nodes around to achieve it.