Pre-step: unfold the rewind crank the next time after you shoot a photo (not the multiple exposure shots) and rewind a bit till taut. Wind your film to observe the range of movement of the rewind crank (leave it unfolded to see how much it moves).
Now to take the multiple exposure:
Take the first shot. Unfold the film rewind crank and rewind a bit till taut. Hold the rewind crank with you last 2 fingers of your left hand.
Using your left thumb press and hold the release button at the bottom of the camera (that's the one where you press in to rewind the film).
Gently advance the film using your right hand.
The last 2 fingers on your right hand is used to hold the film in place, the thumb to keep the release so that the film slips when the shutter is wound. You should by now have brought the shutter to a point where shooting is possible.
After taking the second (or third or thirty third, whatever number you desired) shot, again make sure the rewind crank is taut, now no thumb on the release, gently wind the film one frame. The release button should jump back out, and the film should move 1 frame (you observe the rewind crank the way you did in the pre-step). If the film did not move precisely 1 frame, then shot a blank (put on your lens cap and shot a frame at manual 1/1000 at f16 or f22), wind forward. Then shot normally.
At your own risk...
Or shot normally, scan your film, do the mutiple exposure in Photoshop using layers.
Or shot slides, use a slide copier, put the 2 slides on and do a copy.
Me? I've stopped dabbling in multiple exposure 18-20 years ago. Now if I have to I will do it in Photoshop.