Learn some chords now.

The four common chords:
Major.
Minor.
Diminished.
Augmented.

This may sound weird, but I look on the the four basic chords like 'elemental gods'. Then the amiguous chord(s) and the dominant chord are just minor gods and the others (11, 13, maj7 and so on) are just high beings.

And then you should come to realise that the scales are chords with some extra notes thrown in. Then learn where all the chords are in a scale.

Like the Hindu scale, or melodic minor mode 5, for example. Has a minor chord, a dominant chord, an augmented chord and a major chord. It's major third is the root note of diminished chord. I suppose the scale also has both the amibiguous chords too.

You should learn them all by formula and shape on the fertboard. But getting a grip for melody is more of an organic thing. It's takes a bit of practice, particularly when keeping in scale.

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