There are many options to make a mono signal go to both outputs.
If I understand right the WET signal is the first recording?
The DRY signal is the input to the Mod Duo?
If so the wires are as so.
Switch 1 is dry signal fed to (4 switch) final out, delay 1, delay 2, delay xx.
switch 2 goes to (4 switch) delay 1, delay 2, delay xx.
In this you record/playback delay 1.
Choice to play dry, overdub 1 or record to Delay 2
Choice to play dry, overdub 2 or record to Delay 3
And so on depending on how presets and midi switching is set up
Stopping / erasing any looper is independent.