Also if you’ve configured emulationstation to work with a keyboard you could just use that to access the input controller menu which would be easier.
[off topic] How does one do that? I’d like to be able to control Emulationstation w/ my keyboard.  When looking for the answer for the TS I found it (sudo ~/RetroPie-Setup/retropie_setup.sh And then: “Setup (post install) –> Configure Retroarch controller” (or “Configure keyboard for use w/ Retroarch” to configure a keyboard).). [edit again] That doesn’t work in Emulation station. Only in Retroarch (i.e. when you’ve started a game). => Configure the use of a keyboard in Emulationstation the same way you’d configure a joystick.
[on topic] If you’ve got a spare controller lying around you could connect that one to your Pi and press ‘Select’ –> ‘Configure input’.