An aux track (also known is a aux input) is a mixer channel through which you can route multiple tracks. Audio is sent from the individual track outputs to the aux track using buses, which are simply pathways, through which the audio can be sent inside your DAW. Watch this quick video tutorial to learn how to set up your aux tracks to create subgroups and aux effects:
CLICK HERE FOR VIDEO
This tutorial was created in Pro Tools, but the process is essentially the same in any DAW. Give it a try today!