Remove the wall molding by prying it away from the wall. If you are careful, you may be able to reuse it. Set it aside.
Determine where you plan to start laying the hardwood floor. The longest wall usually is a good choice. Measure 1/2 inch from that wall. Mark the distance with a chalk line.
Set the first row of wood planks in place with the groove aligned with the chalk line. Pre-drill holes close to the grooved side. Space the holes so that the nails enter floor joists, which typically are 16 inches apart. Place another hole in the middle of that spacing.
Secure the hardwood to the floor with 2-inch finishing nails, using a hammer. Use a nail set to place the nail heads slightly below the surface of the wood. Use a pneumatic nail gun to attach the top of the tongue extension to the floor.
Continue to place the planks of the flooring system by inserting tongues into grooves of adjoining pieces. Stagger end joints. When you get to the opposite side of the room, you won't be able to fit the head of the nailer against the wall to operate it.
Set the last row of planks into position. Allow 1/2-inch expansion space along the wall. If necessary, cut the tongue portion off the final row of planks with a circular saw. Use the pry bar to position the planks away from the wall.
Pre-drill holes through the tongue side of the plank. Fasten the hardwood flooring to the floor with finishing nails. Use the nail set to drive any exposed nails slightly below the surface.
Fill the nail holes with wood putty that matches the color of the hardwood floor. Replace the molding around the perimeter of the room. Nail the molding to the wall, not to the floor.