Place your gourd in a dry, out-of-the-way place, such as a garage or a toolshed. Leave the gourd to dry fully for several months. The more humid the location, the longer this step will take. You know the gourd is dried when you can hear the seeds rattling around inside when you shake it. The gourd will also be much lighter than it was when you harvested it. You can bypass this step by purchasing an already dried gourd from a farmers' market.
Clean the surface of your gourd using a metal scouring pad. This will remove any mold that has grown on the gourd. Run the gourd under a stream of water while you scrub. Your gourd is clean when the surface is smooth. Dry the gourd with a towel. After cleaning, you may notice some discoloration remaining. This is normal. As long as the gourd feels smooth, it is sufficiently clean.
Make an entrance hole on the side of the gourd, using your drill's hole saw attachment. According to Amish Gourds, different birds prefer entrance holes of different diameters. Choose the hole size based on the bird you wish to attract to the gourd house.
Scrape away the insides of the gourd using a spoon. Discard the dried innards.
Use a 1/8-inch drill bit to make four holes for drainage in the bottom of the gourd. Exact placement is up to you.
Tie a piece of 24-inch -ong twine around the neck of your gourd. Use the twine to hang up the finished gourd outside.