In the manual it also explains to hold the "shift" key while moving the slider for more smaller incremental adjustments. Or double-click the number and type in the exact amount you want.
Also, if you hold the "cntrl" key when clicking, it resets to "0".
No offense intended. Just play around a little, move the mouse around and stop it from time to time. If you stop the mouse over that section a little tool-tip will pop up that says... coincidentally ...