There are many audio input/output devices on my PC - these include:
HDMI connections
Onboard headphone outs
Capture card connection
Graphics card connection
USB audio interface

Added to that, there seems to be virtual ones as well, so that when I go into vmix to add an audio input, there seems to be quite a list!

My problem is that there are volume & mute controllers outside of Vmix, and I'm never sure where to access these, or which takes precedence. I've got a Behringer USB audio interface, but it doesn't seem to have its own mixer software or anything.

There is the little control panel audio symbol in the bottom right taskbar, but I'm not sure whether Vmix over-rules that - what comes first in the signal chain?

So I'm wondering:

what do you use to manage the audio signals and routing, and are there are any tutorials, apps or resources that help with this?