What is best way for floor sanding
It’s a broad question but I’ll share what I know. Naturally, you want to completely clear the room and take steps to enable ventilation and dust removal. Wear a mask too. I’d start with a low grit (maybe 50) and do a first pass. You’ll generally want to rent a large radial sander to do the majority of the room, but have something smaller to do the edges by hand. If the room has trim and you can remove it, that will help you sand to the edge more effectively.
Generally, I’ve found you want to mop the room after you think you’ve done a good pass, then maybe do another pass with a higher grit sander. That may not be necessary, depends on the damage your floor has.