Calling all aspiring musicians -- and music teachers wishing to give their students some foundational music theory guidance.
Here are two videos that explain and demonstrate how to construct major and minor chords.
The first video is on the piano keyboard, so the prerequisites are (1) knowing the names of the white and black keys and (2) willingness to listen and hear the difference between major and minor chords.
The second video shows a notated illustration. Entry-level literacy and knowledge of major scales are helpful here.