I have looked at one of my Leicinas. The lens converter is removed by pushing the silver button next to it. When replacing, line up the small peg on the lens with the hole at 12o'clock position. The film speed is set on the 'eye' below the lens. The film and motor covers slide off once unlocked. The black button under the handle is back wind. Hold it in, then press the thumb trigger to reverse the motor. The white plastic bit at the back rotates to the left and is a forehead rest! The two cable release sockets are on top. I think red is single frame. If it has a strap on it, the markings are for measuring close focus distance. They are either 3, or 4 inch spaces. There is a film indicator in the viewfinder to tell you when film is finished. I hope you enjoy using it. Alex