Use the root as a reference
Choose a root note near the middle of the keyboard. For a major triad, place the third four semitones above the root and the fifth seven semitones above it. Count every adjacent key, including black keys, as one semitone. C major therefore contains C, E, and G. Play the notes separately before sounding them together. This gives you a way to construct the chord from its relationships rather than relying entirely on a remembered hand shape or a diagram.
Hear the change to minor
Keep the root and fifth fixed, then lower the third by one semitone. C minor contains C, E flat, and G. Alternate the major and minor versions slowly and listen to the changed middle note. Avoid reducing the distinction to happy versus sad, since musical context and performance can change the emotional effect. Sing the third after playing the root, then test another starting note. The physical pattern changes when black keys are involved, but the interval structure remains the same.
Apply the construction inside a song
Choose three chords from a checked AudioChords progression and build each from its root. Use the piano diagrams to confirm note locations if needed, then close the reference and reconstruct them. Play one chord per measure while counting steadily. If a change is difficult, practice the movement between only those two chords before returning to the phrase. Root-position triads are a starting vocabulary, not the only way to accompany a song. Once the notes are familiar, you can rearrange their order for smoother movement while keeping the same essential harmonic identity.