The heart of your smithy, or blacksmith shop will be your forge. Though it is one of the most important tools in your arsenal, this can also be the simplest. People over the centuries have used something as simple as a camp fire with an air source. In the videos below is how to build a break drum forge, the go-to for a lot of beginners. The reason for this is because it is simple and cheap to make, with readily available items, and you can make one without the use of a welder.
If you have the tools like a welder and a cutting torch, then you can make something a little different if you would like.