Thank you, and I did see this response to someone's previous question, but I'm afraid I'm really struggling to interpret this (and I am not totally stupid! I promise!).
I tried selecting sends 33-40, and can get the Main outs (L/R) through outputs 3&4 (not 1&2, for some reason?) but nothing else.
I simply want to use the NSB as a digital snake (for now): all I need are the 16 channels on the stage box to correspond to my 16 desk inputs (which I can do) then outputs 1&2 to be from left and right main outs and the other 6 to be my mix 1-6 for monitors.
I don't see any of this explained in the Presonus set-up video, so I guess I'll probably need to call tech support and have them walk me through it.