I decided to read through threads in the last couple of years, to make sure the information was current.
Here is a set of links to threads that are almost certain to contain the answers to questions in the minds of beginners. I can't stress reading all of them strongly enough. If you do that you will have enough knowledge to go forward with a forge build.
The only thing I will add is that it is not necessary to use an old propane tank with the inherent dangers. A new tank, a freon tank or a