With the 124G version, there are two marks, one for 120, the other for 220, to which you line up the "Start" arrow, winding with the back open. They are both near the roller at the bottom edge of the opening for the exposure frame. With a 120-only camera, we would expect only one start mark. Once you've reached that position, you close the camera, which resets and engages the counter. From there, winding stops at the first frame. (And backing up the crank a bit cocks the shutter.)
I imagine there should be something similar in yours. Best of course to find a copy of the manual.