The desk should not contain much potential for frustrations, but I have to admit there is plenty of functionality inside the box and it takes some time to get into this new world when coming from analog.
One point to start is checking out the block diagram at the end of The Manual. A printed version next to the desk does help to understand the internal routing and how the various sections interact regarding the audio path. Next step would be to understand operation of the surface, i.e. the necessity to select a channel in order to control channel parameters.
If thats all clear, next step would be to understand the routing stuff between the desk and a USB-connected DAW, particularly when routing audio back from the DAW/PC/Mac to the Qu.