The instructions are In the document center.
If you can, remove the furnace
by drilling out the rivets and check both the intake and exhaust pipes for wasp nests. I had one in each.
This will also allow you to check the combustion chamber for cracks and rusted-through areas.
Then, take the burner apart and clean the orifice and burner slots.
After that, it should fire up using the instructions on the document above.
Be careful, and if yo're unsure of your furnace
abilities, have someone check it out to make sure it's safe. (I'm in MN if you're near enough to stop by for a check.)
And if you decide to get rid of it and replace it with a modern one, let me know, I'd love to have it for spare parts.