Jeanette,
Sounds like the wrong Minnesota A manual as it was badged under 3 or 4 makers. Here's one for the "B" or "Burdick" which is the closest free manual available. Some of the pics are of the "A" (bottom oiling chart) and I've never seen a Davis bobbin winder without a thread guide as pictured in one diagram but it should work.
Jon
http://www.sil.si.edu/DigitalCollect...f/sil10-37.pdf