Switch the radio on and the word CODE should appear in the display
Repeatedly press button 1 until the correct first digit of the code is displayed. Repeatedly press button 2 until the correct second digit of the code is displayed. Repeatedly press button 3 until the correct third digit of the code is displayed. Repeatedly press button 4 until the correct fourth digit of the code is displayed.
Once the code has been correctly selected on the radio's display, press button 5 to enter.