When threading a Singer sewing machine, start by raising the presser foot and turning the handwheel towards you until the needle is at its highest position. Place a spool of thread on the spool pin and secure it with a cap, ensuring the thread is able to spin freely. Take the end of the thread and guide it through the thread guide at the top of the machine, then down through the tension disks before pulling the thread down and around the check spring, and then back up through the take-up lever. Guide the thread back down through the thread guide and thread the needle from the front to the back, leaving a tail of thread about 4-6 inches long and trim it. Finish the job by lowering the presser foot and plugging in your machine.