Additional controls = additional confusion for people not used to them. Doesn't matter if they know how to use a smartphone. The guy is a beginner after all. There's a reason why even on this forum most people don't tend to mess with the deeper parameters.
The layout is pretty self explanatory - I just googled the top view. OP can show him how to dial in the sounds he may want, and past that he can experiment. It's not too complicated.