reharmonization is the process of changing the chords underneath an existing melody. Thanks to it, a simple pop song can sound like a complex jazz composition.
How to start? The foundation is the awareness that every melody note can fulfill a different function. If your melody note is "E", you can harmonize it in many ways using chord building formulas.
For example, if you want the note "E" to be the third (3) of a chord, the Reharms trainer will help you quickly determine that the chord root must be C. If it is to be the fifth (5) - the root is A.