We dug a hole 2 feet wider than the fire pit--about 7 feet across. Make the hole round by hammering a stake into the center of your fire pit area. Loop a 3 1/2-inch length of string over the stake and mark the circle. Dig out 12 inches of soil. Shovel in 4 inches of gravel and 4 inches of sand. Tamp that layer flat. Onto that base, lay down the base course of blocks. Make sure this course is level in all directions. Fill the space outside of the blocks with gravel. This nearly buries the first course, making the stone base strong.