Strip the Old Finish

• Rent a drum sander with 60-grit and 100-grit sandpaper. Start with the rougher 60-grit paper, taking up the gloss finish off the floor and starting to dig into the stain underneath. Sand with the direction of the floorboards, starting at one side of the room and working your way across. Once all the gloss and some of the stain is off, go back over the floor with the 100-grit paper to take up the rest of the stain and smooth out the floor. Continue until the floor is down to bare wood throughout. Thoroughly vacuum up the dust.
  
  

Staining

• Put on rubber gloves and open your wood stain. Start in the corner farthest from the door of the room. Working in sections, brush the stain on heavily with the grain of the wood, letting it pool. After a minute, wipe it off with a rag or paper towels. If the stain is not as dark as you want, let it sit a little longer. Do the whole floor; let it dry for at least a day.
  
  

Glossing

• Buy a floor-grade clear polyurethane gloss and wide lambswool applicator. Open the can and gently stir it (don't shake it; that will cause bubbles to form). Brush it gently along the edges of the room, with the direction of the planks. Then pour a line of gloss near the far wall as wide as the applicator (usually about 3 feet), across the widths of the planks. Use the applicator to carefully drag the gloss across the floor. Repeat and continue until the floor is covered with a thin layer. Let it dry for a day. Lightly buff the surface with 220-grit sandpaper to help the next coat adhere, then apply the second coat in the same manner.