Secure two 2-by-4 boards together if the pool is wider than the length of one board. Place the two 2-by-4 boards end to end. Place one 12-inch scrap piece of board on either side of the 2-by-4s. Secure the scrap boards to the 2-by-4 boards with screws.
Lay the connected 2-by-4's on the ground where the pool will be. Place a level on the lower end. Lift the board up until the level shows that the board is level. Measure the distance from the ground to the bottom of the board. Use the calculator in the first reference to determine how much sand is needed to level the area.
Measure the length of the two 2-by-4 boards and divide by two to find the center. Drill a hole through the center using a 3/8-inch drill bit. Center the hole over the area the pool will be installed. Hammer a 3/8-inch rod through the hole and approximately 4 inches into the ground.
Dump sand at the lowest part of the ground you're leveling. Use a metal rake to spread the sand over the pool area. Hold a level on one of the boards. Push the board into the sand until the level indicates that the board is straight. Pull the board toward you to begin leveling the sand.
Work your way around the entire perimeter of the pool. Always pull the board toward you so the sand it drags along fills in your footprints. Use leveling sand from the center point all the way out to the end of the board. Once completed, the board should spin levelly around the entire circle.