If you connect your console to your laptop/PC/Mac via the USB port and adjust your computer's settings to see the DN32-USB as a sound card, it will only pass two channels of audio (effectively your stereo Left & Right outputs from the console)

If you wish to access all 32 channels of audio, this can only be done via the set-up of your chosen DAW (Digital Audio Workstation) on your computer such as Cubase, Protools, Reaper etc.