How to open the old pedal sewing machine?

Winding: Take the thread down from the top, wind it on the gong wire, then thread it into the iron ring that jumps up and down, and then thread it into the eye of a needle.

Off-line: open the upper iron plate, reach in from below and take out the clue sub-library, put in the rope full of thread, squeeze the thread out of the rope library and put it into the machine.