@Boycey
How do you get input from anything external with the mac?
To do it from the Qu attach cable to the output (eg mix) you want to use.
Make sure that mix includes the mike music yada yada you want.
Read the Qu manual if needed to see how to set up a mix.
Note: pushing a mix button is like having a separate layer to adjust on the surface.
unmute what you want in and mute others. adjust levels on the ones selected.
the manual has more if you need it.
Insert adapter on the Qu cable to match the connector and level the mac expects.
From there on this is a mac problem.
Read the software manual for whatever program you are using in the mac.