Here you can see all the different plumbing pieces. On the right is the hand sprayers. On the left you have the main shower sparyer nozzle up top, three diverter valves, three body sprayers and temprature controller.
The valve on top controls water flow to the main shower nozzle. The middle valve is for the water to the body sprayers and the diverter valve on the bottom sends water to the hand sprayer.