Peabody is right, I have 4 pads assigned as snares, I have 4 pads assigned as HH, I have 2 ride pads, and 9 tom pads. I have other sounds assigned to the other pads on my ZX, but like peabody said, there is no wrong way to do it. I found my layout by tapping my fingers and palms on a table top. What I found is that I use my thumb on my right hand to go back and forth from kick to snare, and my right ring finger does the 8th notes on my HH. With that I can do a one handed groove. I use my left hand for what I call "ear candy". I can add kick patterns and 16ths on the HH or tripletts on the snare.
Like Peabody said, find your natural rhythm and ergonomics to determine what position and setup is best for you. Everyone I have come across plays their Zendrum totally different. It is not a drum kit and there is no standard way of doing it, futureman plays his ZX upside down, that is just how he plays, and it works for him.