how to install wood floors?
Your question cannot be answered in detail as you ask it. First of all, what kind of wood floors are you taking about, 3/4 hardwood, 3/8 hardwood, laminate, engineered flooring. . .what? Second, what are you installing the floor over, wood or concrete? That will determine what kind of flooring you can use. Finally, there are certain ground rules that are common to most wood flooring. First, make sure the subfloor is level. If you have peaks and valleys in your subfloor, it will stress the flooring and cause premature failure. Know what kind of moisture barrier you need. This will depend on whether the flooring is in a dry (living room, etc.) environment or a wet one like a kitchen or bathroom. Pay attention to the maximum height of your flooring and use the underlayment thickness that will get you to the right height. Keep flooring about 1/4 away from walls to allow for flooring expansion and contraction with moisture and temperature. Finally, for wood floors, allow the flooring to come to temperature in the room it will be installed for at least 72 hours. I strongly suggest you do your homework and research what kind of flooring you want, and what will be best for your application. Unless you have the fundamentals down, you are wasting our time with a non-specific question such as yours.
We had a 12' x 14' room that had a horseshoe pattern that was out by 3/4. I ripped 2 x 4's at an angle to create 6' long shims, so the shims were 2 (1-1/2) wide x 3/4 to feathering out to nothing x 6' long . We had removed the old carpet so all we had was the original floor sheathing. I then screwed the shims down to the floor joists and used a pour in leveling compound to fill in between the shims. Let it dry a couple days and laid laminate over the top. If you use a pour in leveler any little holes or around floor ducts you will need to seal up so the leveler does not flow through. I happen to ruin a ironing board & iron that was in our basement because it leaked through, didn't find it until the next day!!