How do you set a Rethyo watch?

If it is the same watch as mine the winder is at the 3 o'clock position - the key has a double "keyway" on it. Insert as if to wind normally, push down and turn clockwise - you'll feel the keyway lock in. Then using some force, pull the key outwards and you can now set the time. (You can only go clockwise or the keyway unlatches)