Kenmore 1203 Instructions Manual page 10

THREADING UPPER MACHINE
Place thread as illustrated between discs of the Thread
Tension Control. Prevent the spool of thread turning
and by holding the end of the thread pull spl_ng wire
loop clockwise past the top hook, then, pull thread
to left so that the thread can slip into the hook.
When thread tension is released, the spring wire loop
will return to position as shown with the thread in
proper place.
Release spool of thread and continue to thread
machines as illustrated.