I2S Theremin

How do you go about connecting the sliders as shown in the schematic? The sliders only have 3 connections and it doesn't look like there is a way to connect them as shown.

A "Theremin" is a "hands off" instrument generally accepted to use RF or capacitance or light feedback to influence the sound. think maybe the title is misleading. Looks more like a simple oscillator that is manually controlled.

Warning, I thing your schematic is wrong, I didn't succeed with your example. I recommend to use this schematic https://www.arduino.cc/en/Tutorial/I2SSimpleTone