Zorki 6 question

[webb3201]

I was working to learn my Zorki 6 tonight, but I have one question that I cannot find out from the manual. This may be really stupid, but what is the left hand knob for? I can figure out where the aperture, film speed and counters are located, but I cannot find a use for the left knob. I am sure I will feel silly when I get the answer, but it is late and I am tired of thinking it through alone.

 

[digitalox]

this help?

http://www.rugift.com/photocameras/manuals/zorki-6.htm

 

[Solinar]

The knob on the left rewinds the film, after you press and hold down the button beside the shutter speed dial.