Sand the wood floors to create a grip effect. The sanded floors will serve to grip the spray when applied. Use an electric hand sander or an industrial-strength sander to lightly sand the floors, keeping the job even and consistent.
Build a spraying booth to keep the spray from coating walls and furniture. Duct tape together six 4-foot by 6-foot cardboard panels, and top it off with a large piece of cardboard to serve as the lid. These panels will need to be moved with you as you spray, serving as a shield of sorts for the walls and other items in the room.
Open any windows in the room and, for further protection, place a box fan in each window. Make sure the fan blows toward the outside of the house when you turn it on or the fan will be counterproductive. This will serve as a vacuum for the fumes put out by the spray gun.
Set the nozzle on your spray gun to a low pressure to create a misty spray (not a pressure spray) when you pull the trigger. This will allow a more even and accurate coat on your wood floors. Pressure sprayers are effective in some settings, but for spraying a wood floor in a room, low-pressure spray is the best approach.
Starting in the back corner of the room--meaning the farthest spot from the door--begin applying an even and smooth coat of spray finish, keeping your arm moving back and forth constantly to avoid spraying too much in one spot. Let dry for about 24 hours.
Apply another coat if needed using the same steps practiced in steps 4 and 5, also using the fumes booth and all of the protective attire you used during the first coat.