Chord Progression
Chord progressions take two, three, or four Chords of a Scale and loop them in a particular order (e.g.: 1-6-4-5
aka. I-vi-IV-V
).
While that progression is playing our other instruments align themselves based on it and when the next chord starts they also adjust. This creates emotional impact while keeping all the instruments in harmony.
The length of how long each note is played can be varied, as long as it stays consistent with the other instruments, and also not all notes of the progression have to be played. The Progression holds everything in harmony in the background, so you are free to for example only play the lowest not for the bass and maybe skip the second note for the pad.
To find chord progressions, I can recommend using free MIDI packs like this one ldrolez/free-midi-chords or use chord progressions from existing songs using websites like Ultimate-Guitar, Chordify or just googling for them.
Relevant Note(s): Chord Inversion