Run a vacuum cleaner across the wood floor, scooping up all dust, crumbs and dirt. Fill a bucket with warm water and dip a mop in it, dampening it slightly. Mop the wood floor lightly; you don't want to saturate the wood, just remove any dirt the vacuum cleaner missed.
Put on your goggles and dust mask.
Attach a piece of 60-grit sandpaper to the bottom of the machine. Wheel the machine to the far left corner of the room and plug it in. Before you switch the machine on, hold the handle and tilt it back towards you, so it's off the ground.
Adjust the machine so that it's lined up perfectly with the corners of the room and switch it on. Move the square buff floor sander in a straight line from the left end of the room, ending back at the right end of the room. Keep the machine moving and work back to the left end of the room, moving in a straight line. Continue in this manner until you've covered the entire room and then repeat with 120-grit, 220-grit and 360-grit sandpaper.
Run a vacuum cleaner across the entire room when finished, removing all the dust from sanding.