A major triad has a major third above the root. This is 4 half-steps or 2 whole-steps above.
A minor triad has a minor third above the root. This is 3 half-steps or 1 whole step and 1 half-step.
Both triads have a perfect fifth above the root.
So C major consists of C – E – G, and C minor consists of C – Eb – G.