How do I activate and deactivate the childproof lock?

To activate or deactivate the childproof lock, touch and hold both the 0 rpm and Finish in (û) buttons simultaneously for approximately 3 seconds. When activated, the symbol 'w' appears on the display, and if the button signal is on, an acoustic signal will also sound. Note that the childproof lock may remain active even after the washer dryer has been switched off. (Page 18)