Kimunor

I was given this old Kimunor 135 mm lens attached to an old Zenit camera a while back. I haven't used it, and this photo shows two reasons for that: I find these rings confusing; both seem to have something to do with aperture. It's a preset lens, I think, but I can't figure out what that means, or how to do it.

Perhaps I should spend some time learning, and getting to know it...