What safety precautions should I follow when replacing the needle?

Always turn off the machine before changing the needle to prevent injury if the foot controller is accidentally pressed. Before replacing the needle, place fabric or paper under the presser foot to prevent the needle from falling into the hole in the needle plate. Insert the needle with the flat side toward the back of the machine until it touches the stopper, then securely tighten the needle clamp screw with a screwdriver. (Page 1)