Cut a perfectly round 6-inch hole on the top of your wooden rain barrel, using a 6-inch hole saw, keyhole saw, saber saw or drywall saw. Then drill two holes in the barrel using the 29/32-inch drill bit. One near the top will be used as an overflow; the one toward the bottom is to place the faucet.
Twist a ¾-inch NPT pipe tap into the upper hole, then untwist the tap and back it out of the hole. Do the same for the lower hole.
Rinse out the wooden barrel using 2 tsp. of mild soap and 2 tsp. of vinegar (or lemon juice) per gallon of water.
Twist the threaded side of the hose adapter into the top 3/4-inch hole. Wrap the threaded side of the brass fauct with Teflon tape, with enough rotations to cover all the threads.Twist the prepared end of the faucet into the hole towards at the bottom of the barrel.
Cover the 6-inch hole in the top of the barrel with a 6-inch louvered screen, screen side down. This will help prevent mosquitoes from breeding in your rain barrel.
Place a hose onto the adapter at the top of the barrel; this will direct the overflow water away from your home.
Put the cinder blocks under the gutter downspout and place the barrel on top of them. Then cut the downspout about 4 inches above the top of the wooden barrel before adding the elbow and making any final adjustments that are needed.
Place a hose on the faucet for redirecting the water to a watering can or other container.