Ensure that both thumbsticks are untouched and centered. Press Enter.

Tap on a blank desktop area to move the cursor off of the Konsole window. Make sure Konsole isn't in focus.

Rotate each thumbstick through a full rotation (360 degrees) twice.

Tap on the Konsole window to bring focus back to it. Press Enter.

That's it! Your thumbsticks are now calibrated. The terminal should say "Thumbstick calibration successful."