Connect one input source to each channel strip. Your channel strips are the vertical columns appearing on the mixing board, and input sources include instruments, microphones, turntables and any other devices from which you may transmit music. When you connect an input source to an audio jack on a particular channel strip, you can then use the controls on that strip to control the settings of the input source.
Adjust the volume of each input source. Some inputs will naturally project more loudly than others, and you can use the "Levels" sliders to bring your different inputs into balance with one another. For example, if the bass drowns out your guitars in a live band arrangement, you can reduce the amount of bass by sliding the "Levels" (sometimes "Volume") slider downward.
Pan your inputs appropriately. Your "Pan" knobs allow you to adjust the placement of each input source. For instance, if the indicator remains in the center, the sound will transmit equally through the left and right channels (speakers). If you move the knob counterclockwise, the sound will become more emphasized in the left channel, while clockwise adjustments will move the sound into the right channel. Use the "Pan" knob on each channel strip to adjust the placement of each input.
Equalize your input sources. Portable mixing boards typically have three EQ knobs: one for bass frequencies (80 Hz), one for mid frequencies (2.5 kHz) and one for treble, or high, frequencies (12 kHz). Larger mixing consoles will often have many EQ knobs, isolating more precise frequencies. By adjusting these knobs, you can alter the presence of your frequencies, whether you need to reduce excess bass or brighten the sounds of violin strings.
Monitor your mix with precision using your "AUX" or auxiliary knobs. While sampling your overall mix prior to a live performance or studio recording, you may want to hear certain channels isolated from the rest. You can do this by raising the auxiliary level in your desired channel(s) while reducing the auxiliary level in the channels that you wish to suppress.