Hi RRRoger! Welcome to our tractor internet forum. I'm glad you found us.
I've tried searching for a free site for a wiring diagram and have not found anything worthwhile. Lots of places want to sell you one though.
I'll suggest going back to where you purchased the alternator. They should be able to give you some guidance on how it should be hooked up.
Otherwise maybe someone here will chime in with some experience of their own.
What Ford tractor are you putting the alternator in?