Sand the surface of the flooring with a hand sander. Use the lowest setting possible and only fine-grit sanding pads. It will take longer, but you will not run the risk of breaking through the veneer layer. Sand once, with the grain.
Sand the edges of the floor with an edge sander. The hand sander will not get into the edges in the room. Use the lowest setting and lightly sand the edges until they match the rest of the boards.
Clean up the sanding dust with a vacuum and tack cloths. Vacuum the floor to remove the larger particles of dust. You may need to do this twice to get it all up. Wipe each board clean with a tack cloth.
Stain the wood the desired color. A floor stain applicator helps you get an even coat without brush marks, but you can use a brush if you prefer. Go with the grain of the wood and apply a light coat. Let this coat dry for four hours. Do not allow any foot traffic on the floor.
Sand the floor lightly with a fine-grit sanding block. The finish needs to be roughed up slightly for the poly coat to adhere properly. Wipe up the dust with a tack cloth before proceeding.
Apply polyurethane to the floor. Use a clean floor stain applicator. Apply the polyurethane coat just as you did the stain. Go with the grain of the wood. Let this dry for up to 12 hours. If you desire another coat, sand lightly and apply the second coat. Let the floor sit undisturbed for up to 24 hours to give the polyurethane plenty of time to dry.