How to adjust the date on an old Citroen C-Quatre?

[JasperLee]

After the dashboard powers on, locate the CLK button (displays and sets the time), then press and hold CLK for approximately 5 seconds until the time display starts flashing on the screen. Use the adjustment knob (turn left to decrease, turn right to increase). After setting the time, press the CLK button once to confirm. The adjustment mode will automatically exit after a few seconds of inactivity.