There are a couple of ways to season iron pans.

The way they did it in the old days of our grandparents was to build a large fire and place the pan in the fire for several hours. Once the fire was burned out and the pan cooled enough, it is covered in oil or some kind of cooking fat or grease.

The way I do it when I buy a new iron pan these days is by taking a paper towel and pouring cooking oil on it then rubbing it all over the inside, as well as the outside of the pan. Then I place it in my oven, at a very low temperature, around 150-200 degrees and leave it for four or five hours.