Wow - made in Japan! It threads just like any other machine. Thread goes from the spool, across, down around the tension & tension spring, up through the thread take up lever and back down through the needle. Needle threads from the left to the right. I'm not exactly sure about the red knob but I think it sort of helps set the zig zag in combination - 2 knobs and lever - just experiment - one knob probably holds the lever in place. Some times the extra knob will be button hole settings. (Usually if it has a cam stack it is closer to the upper left.) The long lever on the right is the stitch length. Can you shoot a close up of the control knobs and levers on the front right of that machine? It would be VERY difficult finding the same manual as your exact machine: There is a generic manual somewhere on this thread:
http://www.quiltingboard.com/vintage...s-t207877.html