How do I reset my KLIK radio controlled alarm clock?

How do I reset my KLIK radio controlled alarm clock , after changing the battery.
There is a hole at the back with 'reset' marked underneath' One is supposed to put a long object inside and hold.
I put in and a hairclip and held for different times, but no luck.
There is no Model Number, only KLIK.
It is halfmoon shape.