I would like to add a zone to a oil-fired forced hot air system

That would be nice, do you have any questions?

I'll let you much on this URL for awhile: EWC Controls

Zoning should contain a bypass damper. It connect supply and return air.

If it's just one room that gets too hot or too cold, You can just motorize that one damper without a zoning control.

After you munch, you can come back with questions.