Please explain the rules of chord combination, where to use it in music, and whether to remember all kinds of chords when playing guzheng.

This. . A major chord is usually an octave. Generally used to cooperate with the left hand, or to strengthen the role of the right hand. If it is regular, I think it means that the hands are naturally relaxed. The first and last tonic strings are right, and the strings that the rest of the fingers relax are generally other notes of the chord. You don't have to write it down. I never write it down on purpose. You'll know when you play too much.

If it is a pinch of two sounds, it is usually the right hand, and there is a string between the two sounds that is right. . .