I would like to know what tools, flux, solder to use when soldering ferrous wire. The only directions I can find are for NON-ferrous wire. Thank you.

It depends a lot on the application. Jewelers will use silver soldering/brazing with a real small torch.

Jewelry Making Supplies | Soldering - Silver Solder Equipment, Smith Little Torch

The alloys and flux depend on what's being soldered and it's application.

I've done it on a larger scale. It's difficult for some people.