I actually FOUND this same model machine yesterday!!! Just missing all but the basic cam!! And she worked beautifully. Found it just sitting in the grass in a shopping center parking lot outside a joann with a free take me sign on it

I just came across your video, the presser foot that you said you don’t know what it’s for is for sewing on buttons if you haven’t found out already from anyone else.

Looks like you missed putting the thread into one of the guides above the needle.

I can send you an image of the user's manual for this machine. The one that illustrates proper threading.

cool old machine, look for a serial #, might help you happen across more information