Singer 9420 explaining what the levers, knobs, dials and switches are for

I will help you understand all the button's knobs, switches, dials, levers on the front of the Singer 9420 Sewing machine. How do you change settings, how do you stitch in reverse, how do you stop the needle from raising and lowering, how do you change the stitch length, width, or balance? What are they? I will describe each one and explain their use. What are they used for, what do they do? when do I use it? I