I suggest you download the M32-Edit, its easier to look at. Attached is my setting on recording on an SD-Card. But you can change the setting to Playback USB-Interface and whenever you are recording, change the Channel Routing to Recording. If you want to playback change Channel Routing to Playback. You can also choose the USB-Interface to determine how many ins and outs you want to assign in your DAW. If you are recording on a SD-card it will record only one wav file but its multi-channel. If you import it on your DAW it will automaticaly create 32 channels(or whatever you set on your SD-Recording option).