on my manual 1581 kenmore show figure on how you thread your bobbins and upper thread.
to thread bobbin insert the thread on one hole of winder holding thread and rotate thread on counter clockwise rotation several times, loop the thread on tension thread and insert bobbins winder on winder shaftat top of your sewing machine push the latch to lock bobbin winder
pull the handwheel to disengage the clutch and to move the winder free rotation.
press the foot pedal to run your winder and thread your bobbins be sure on counterclock wise rotation.
if winder is full of thread this will automatically disengage the shafting winder from clutch.
insert winder as in fig. check the thread direction
on figure hold and insert bobbins on shuttle race assymble.
on figure show upper threading.
follow the red thread on figure.
you can also check your manual on internet
search box type www.kenmore
have a nice day,rate my fix,thank's a lot