The answer to 'how to maintain hardwood floor' is to regularly clean and protect the surface. This includes sweeping, vacuuming, and damp-mopping the floor to remove dirt and debris. You should also use a hardwood floor cleaner and apply a protective finish every 1-2 years to keep the wood looking its best.
It's important to avoid using too much water when cleaning hardwood floors, as excess moisture can damage the wood over time. Stick to a damp mop rather than soaking the floor. You should also avoid harsh cleaners or abrasive scrubbing, which can scratch the surface.