How do I build a fire pit?

I have a fire pit that I occasionally cook over in my yard. I dug a hole in the ground, 4' in diameter and 12" deep. I have field stones around it. To cook, I made a hanging grill. It's shaped like an inverted L. I drove a pipe in the ground a little larger than the outside diameter of the pipes that the grill hangs from, then attached 2 pulleys to it, one at the end of the l, one in the inside corner. I ran a small steel cable through both pulleys, which I can use to raise and lower the grill. There is an eye on the end of the cable, which has 3 small chains attached to it. The chains clip on to a 22-1/2" Weber grill, which I use to cook. For fuel I just use firewood. After I am done cooking, I can pivot the grill out of the way and let it cool. Feel free to e-mail me if you have any questions. Hope this helps.