Things You'll Need
Hammer
Flatbar
Flooring felt
Razor knife
Staple gun
Level
Pencil
Tape measure
Tongue-and-groove floorboards
Drill with pilot bit
2-inch spiral finishing nails
Nailset
Miter saw
Rubber mallet
Hand-held electric nailer
Hardwood flooring is usually installed by three methods of nailing: hand-nailing the first and last courses, because they're too close to the walls to use power tools; power-nailing the courses alongside the first and last ones, because they're still somewhat close; and installing the whole center of the room with a full-sized pneumatic floor stapler, which can't be used within 3 or 4 feet of a wall but makes the job go very fast once you bring it in. The process is the same for a small closet--except you can't use the floor stapler at all.
Step 1
Use your hammer and prybar to remove the floor trim from the closet floor. Don't break it, so you can re-use it at the end. Spread your flooring felt over the floor, cutting it to size with your razor knife. Staple it down with your staple gun.
Step 2
Lay your level next to the longest wall in the closet and mark a pencil line along it, 1/4 inch from the wall. This will provide a gap between the floor and wall, which you have to maintain all around the closet to allow the floor to expand.
Step 3
Lay your first piece of flooring on your marked line, with the grooved side facing the wall. Drill pairs of side-by-side pilot holes every foot or so along the board's surface. Hammer 2-inch spiral finish nails into each of the pilot holes. Set them below the surface with your nailset. Cut a second floorboard to size on your miter saw to put at the end of the first one, leaving a 1/4 inch gap at the end, and install it the same way.
Step 4
Lay your next courses of floorboards by tapping the tongue-and-groove sides of the boards together, holding them tightly in place with your prybar, and using your hand-held electric nailer to sink nails into the sides of the boards at a downward angle. Put a nail about every foot. Cut the end pieces as needed, leaving your 1/4 inch gap at the walls.
Step 5
Lay all the flooring across the closet floor with your hand-held nail gun, until you get to the final course. Top-nail that course, as you did the first one. Re-install the floor trim to cover the expansion gaps at the walls.
Warning
Wear goggles when using a nailer.