unscrew the n°4, of the number of turns counted at step 4), then put in place and screw fully n°3, put the bonnet and screw n° 2.
Warning : don't unscrew too much the n°4, or it will fall.
I fixed actually a 500 CM; other C bodies are probably similar, but I can't give any full advice on them.
I formerly made a mistake in the scheme D), as I had drawn it from memory mind, from a jamming that occured some years ago. It's now correctd, thanks to a reader. I apologize for inconvenience.
Be very carefull not to let the screws fall in the mechanism. They are prone to slip in the right side, where stand the winding wheels. I suggest to keep the camera on its left side while unscrewing screws n° 2 and 3, with your hand keeping the front half up.
It would be fair to give the camera to a repair station to check it and lock the screws with special varnish.
If both operations haven't unjammed the camera, going to a repair station is mandatory. While travelling abroad and can't find an authorized place, you may visit a watch repairer as a joker.