@DLane is right about what will be needed (sorry I left you waiting Mr Tex 
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@rmadrid20 In case you miss it in the small print of the indexing valve writeup, we both linked to, Rachio Flex schedule will not work with indexing valves. So you can continue using the valve without upgrading it, but only the Manually set schedule would be supported (indexing valve does not allow you to water a specific zone, without watering every zone in between). Flex schedule waters the zones as needed, rather than by predetermined schedule and water needs of each zone go out of sync with each other pretty quickly (due to plant / shade / soil differences).
If you choose to upgrade your valve, a three zone assembly (link) is widely available. You can likely find one in your local home improvement store.
You will also need a matching Valve box, if you wish to hide your valves underground. Considering that they are by your pump, you could install them above ground and greatly reduce the effort / cost required.