There are two mixes, a right audio channel main mix for the congregation (known as the front-of-house mix) and a left audio channel band mix, which also has a number of click tracks and cues to use as foldback for the band. These mixes are completely independent of each other.
By default the main mix is set with everything flat and the band mix just has the clicks and cues audible.
The basic idea is to mute the tracks where you have live instruments playing and then boost or cut the other instrument stems to taste.
Note that the click and cue tracks only play through the Left audio channel in the band mix; they never appear in the front-of-house (Right) mix.
If you are struggling to hear the difference in right and left do check with a pair of headphones.