I can't offer anything specific for a 1939 Diamond T-Model 404 but they are pretty generic and simple.
This Delco Regulator bulletin
in our Photos and Documents Library should help you with your charging system and this Delco Igntion Coils Bulletin
should help with the ignition. The lights, heater, horn, etc. you'll have to work through. If you need help someone here will jump in. Good luck. Pictures would help-- just because we like pictures.