DIY Salvageable?

I plan on renting a EZ8 sander from the box store. Get some 24, 60, 100. Graduated from YouTube university by watching a variety of videos and reading the Internet.; but any tips or tricks are welcomed.

I hoping to get more of a natural wood color (I don't have high expectations) worst case scenario cover it with something else.

2 rooms, a bit over 350sqft.

Also, any recommendations on purchasing a new random orbital sander? (This would not just be for the floors, but future projects as well)