SINGER W102 - Manual (Page 12)

UPPER THREADING
Turn the handwheel until the needle reaches its highest position.
For correct threading pass the thread through the guides and tension
regulator as follows:
Place thread on spool pin and hold spool lightly, allowing it to slip
as the thread is pulled. Bring the thread through thread guide A
down to the tension regulator B and under and between the tension
discs C from right to left and up.
Continue by placing in loop of check spring D and under retaining
bar E.
Continue up and thread
through the take-up lever
F from right to left and
down through thread
guides (2) H.
Be sure to slip thread
into the needle clamp
thread guide I and then
thread the needle from
left to right.