Vortex Sound Research

I can't find any video on this really. Trying to decide on CP or YC, or perhaps something else entirely.

But one thing that I never see demonstrated in videos, is how the aux in works. Can someone explain this to me? With the YC, can you use the drawbars to filter the input, or only add the on-board effects to it? Even more I can't imagine how aux in works with the CP.

Thanks.