If you go back through this thread, you will see a generic manual. The knob at the front top is for zig zag, if you want it to lock the size stitch one of the knobs next to it will likely do that. Since it doesn't lock by itself, you can use the knob to vary stitch width as you sew. The knob with the R is your stitch length and the R is a reverse button. If it is not stuck, it pushes the farthest when the knob is all the way on the longest stitches. The bobbin is a class 15 type so any class 15 manual will work for that.