Open the lid of the pump assembly. Typically the assembly will be on one end of the pool's deck. Turn the valve inside the compartment completely clockwise to stop the flow of water through the lines.
Remove the drain plugs from the pool. Use the tip of a flat-head screwdriver to loosen the plugs from the pool first. Let the pool drain. Return to the pool once all of the water has drained out.
Screw the unclog adapter onto one end of the garden hose. Screw the other end of the garden hose on a nearby faucet.
Enter the pool and remove the screws from around the drain grill, using the Phillips screwdriver. Pull off the drain grill with your hands. Set the grill, screws and screwdriver on the deck.
Turn on the water at the faucet. Insert the unclog adapter at the end of the garden hose into the drain. Push the unclog adapter as deep into the drain as you can, while twirling the adapter clockwise. Pull the adapter up and almost out of the drain. Repeat the procedure three more times before removing the adapter from the drain.
Turn off the water at the faucet. Remove the unclog adapter from the garden hose and the garden hose from the faucet.
Remove any debris or leaves that are now on the bottom of the pool. Place the drain grill back on the drain and reattach the screws. Return the drain plugs into their holes in the pool. Turn the valve in the assembly compartment counterclockwise to resume water flow and put on the lid. The pool can now be filled with water.