Manuals can be had here: {
http://www.singerco.com/accessories/instruction-manuals }
Good help on the top and bottom tensions here: {
http://www.tfsr.org/publications/tec...machine_manual }
Humming could well be the motor as well as the machine needing lubricated. Motor takes Singer Lube only, machine takes oil. Make sure the belt is not too tight.
Needle goes in FLAT to the RIGHT, and is threaded LEFT to RIGHT.
When you put in a filled bobbin and thread the case, hold it with the open side facing you and pull the thread. The bobbin should rotate clockwise.
The machine probably needs a thorough cleaning.