How do I activate the childproof lock?

To activate the childproof lock, touch and hold the buttons for spin speed (0 rpm) and Finish in (û) for approximately 3 seconds. The symbol 'w' will be indicated in the display, and if the button signal is activated, an acoustic signal sounds. The childproof lock will remain activated until the next programme starts, even after the washer dryer has been switched off. (Page 18)