This accessory has 1 pushbutton that breaks out into 1 socket.
This file (pushbutton holder.stl) can be downloaded from the thingiverse page.
I can’t find the link to the pushbuttons I used, but you can find similar ones on aliexpress.
Wiring: connect ground and ‘left’ audio pin (the one farthest away from the ground pin on the socket). to the 2 pins on the button.
Suggestion: stick velcro pads on the bottom and/or sides of the button to stick it anywhere you want it.