Welcome Hamidah.
The wiring to the light looks like it could use some attention. It looks like there is a bracket that is attached to the machine behind the round inspection plate. Without the machine in front of me, it is kind of hard to tell how to get the shade off the lamp socket, but if you unscrew the thumb screw on the round metal plate you will see another screw for the bracket to the lamp. That should give you a better view of the lamp workings. I'm thinking that where the wires go in there is a nut that will unscrew. I think I have a machine with that type of light. If you can't figure it out after you unscrew the above mentioned screws post another picture of the underside.
Janey - Neat people never make the exciting discoveries I do.