You should end up with a folder named prox-sensor-encoder-menu, which should contain a README.txt file and a CircuitPython 9.x folder. Open the CircuitPython 9.x folder and copy all of its contents to ...

It's half USB Key, half Adafruit Trinket, half rotary encoder*...*it's Rotary Trinkey, the circuit board with a Trinket M0 heart, a NeoPixel glow, and a rotary encoder body. We were inspired by this ...