Or do not do what my mother did and she should have known better. Do not be enamored by the face of the watch. Yes it is really important but you need to examine all the surfaces. It was just a dollar, six if you count she had to buy a batteey.
Anyways examine it closely. CHECK for a stem. She did not check and just assumed there was one. Well there was not.
Lesson when buying a used watch check the face, the back to see if its on securely and if there is a stem. The stem is what moves the hands that’s on the side, the knob.