Thanks. Yes I am showing keys built off the major scale. As far as minor keys, the way I generally think about it is that the vi chord (the relative minor) of a major key shares the same key signature as the I of that key. In other words, G (I) and Em (vi) share the same key note signature: “one sharp”. So Em shares the same chords as G. D and Bm are the same keys, C and Am, Eb and Cm, F and Dm, etc. So they will share the same chords, because they are generally the same chord family.

Traditionally, minor keys will be built off the root note, thus Em will be the scale: E F# G A B C D E, and we can build the chords off of that minor scale. And between the 1 and 2 will be a whole step, the 2 and 3 a half, etc. If you like it better, there is a half step between the 2 and 3 notes, and the 5 and 6 notes. Also, we would have a chord structure like this: i, iidim, III, iv, v, VI, and VII, where the lower case roman numerals are minors (the ii being diminished) and the upper case being majors.

Thus, the key of Cm would be: Cm, Ddim, Eb, Fm, Gm, Ab, Bb.

A big HOWEVER here, there are different types of minor keys/scales. The one I’m referring to is the natural minor scale, and generally follows this rule. But many times even the natural minor will break the rules, and convert some of the minor chords in its family to majors or sevenths.

Let me know if this helps, or if you have any other questions.

David