pH to H3O+ and OH values?

When pH = 3.35 :
[H₃O⁺] = 10⁻³˙³⁵ M = 4.47 × 10⁻⁴ M
[OH⁻] = Kw / [H₃O⁺] = (1.00 × 10⁻¹⁴) / 10⁻³˙³⁵ M = 2.24 × 10⁻¹¹ M
The solution is acidic because [H₃O⁺] > [OH⁻]

When [H₃O⁺] = 2.28 × 10⁻² M :
pH = -log[H₃O⁺] = -log(2.28 × 10⁻²) = 1.64
pOH = pKw - pH = 14.00 - 1.64 = 12.36
The solution is basic because [OH⁻] > [H₃O⁺]

When [OH⁻] = 3.31 × 10⁻⁴ M :
[H₃O⁺] = Kw / [OH⁻] = (1.00 × 10⁻¹⁴) / (3.31 × 10⁻⁴) M = 3.02 × 10⁻¹¹ M
pH = -log[H₃O⁺] = -log(3.02 × 10⁻¹¹) = 10.52
The solution is basic because [OH⁻] > [H₃O⁺]

pH below 7 means it's acidic. Between 7 and 14 it's basic.
Concentration of H3O is obtained using this: [H3O+] = 10^-pH
You also got this: [H3O+] x [OH-] = 10^-14 at 25 degrees only. If you're at 25 degrees C you should use this to find the concentration of OH-.
To find the pH, you use this: pH = -log[H3O+] but only when pH is between 2 and 6 or between 8 and 13 as this rule doesn't work when there's too much concentration of either OH- or H3O+.