Stereo 3 Volume

I figured out how to use a USB drive to input music, and it reads the drive. But I cannot figure out how to adjust volume on stereo 3 (It is currently set to 0 and I cant play anything.) How do I adjust the volume!?
(I have a QU-32 Btw)

You need to go to the source selection menu and select Q Drive to ST3.
Source selection can be accessed from any channels pre amp menu.