The Rachio 3 is usually controlled from a smartphone app which provides access to all the capabilities of the system. But occasionally, someone (you, your irrigation professional, etc.) may need to run or test the system manually from the controller itself. There is a single button that has a left, right, up, and down action. Moving left to right cycles through your zones, as indicated by a small light just above the zone number. The down button starts and pauses that zone, and the up botton stops that.
Below is an article on the Rachio site that provides more info…