Basically, the mixing desk is where all the sound sources (microphones and instruments) need to be connected, so that the sound engineer can adjust their respective volumes to produce a well‑balanced mix.

Each microphone on stage needs to be connected to one of the mixer's MICROPHONE inputs; if you want to connect musical instruments like guitars and keyboards that have a 'jack' connector (the proper name is 1/4" TRS) you will need to use a D.I. box to come out with the connection and level that can be accepted by this mixer.

Each channel has its own set of controls, so you can tweak and adjust each sound as they get all mixed together into a Master Channel (controlled by the L&R Fader on the right-hand side of the desk).

The L&R Mix fader controls the level of the stereo mix that comes out from a couple of connections at the back of the mixer, and this is where you make the connection to the main speakers.

Any mixer is, fundamentally, a box with quite a few inputs and at least one stereo output.

In reality there will also be additional inputs and outputs to be used for adding artificial reverberation and other effects, and for monitoring (i.e. sending reference mixes to the performers on stage). But let's ignore all that right now.

EXERCISE 1: FIND THE CHANNEL INPUTS

Looking at the back of the mixer, identify the inputs for your microphones and instruments.

You could connect a microphone to one of these inputs to see if you can get any signs of activity on the mixer's display, but there are still many things that may need to be adjusted befoere this is going to work.