Plug the encoder assembly into a known good data USB C cable. Plug the other end of the cable into a computer or tablet. When you turn the encoder, you'll be able to adjust the volume on the device.

Going Further

The code is meant as a simple example. You could change it to send different HID inputs, maybe for a video game, or change out the QT Py RP2040 for an ESP32-S2 or S3 to try sending commands over Bluetooth instead of USB. If you do build on this, consider documenting it as an Adafruit Playground note!