I'll make it easy with triads... A major triad is a chord that includes three notes, called the root, the third, and the fifth. In a D Major triad, the D is the root. With Major triads the interval between the root and the third is four half steps, and between the third and the fifth is three half steps. So... D (+1 half step) D# (+1 Half step) E (+1 Half step) F (+1 Half step) = F#. So F# is the third. Then we move three half-steps up from F#... F# (+1 half step) G (+1 half step) G# (+1 half step) = A. So the D major triad includes the notes D, F#, and A. Now when you're forming a minor triad, you just take the third of the major triad and lower it a half step. This changes the interval from the root and the third to three half steps, and increases the interval from the third to the fifth to four half steps. So changing D major to d minor is as simple as either lowering the third a half step or flipping the interval location of the Major triad. I added bold tags around the root, third and fifth: D (+1 half step) D# (+1 Half step) E (+1 Half step) F (+1 Half step) F# (+1 half step) G (+1 half step) G# (+1 half step) A - D F# A - D Major D (+1 half step) D# (+1 Half step) E (+1 Half step) F (+1 Half step) F# (+1 half step) G (+1 half step) G# (+1 half step) A - D F A - d minor Now, once you've got that down, augmented and diminished aren't much different. First, when you diminish something in music you lower it one half-step. When you augment something in music you raise it one half-step. When using diminished and augmented triads, you are affecting the fifth of the chord. However the only tricky thing is when you're diminishing, you're affecting the minor triad and when you're augmenting you're affecting the Major triad. So you take d minor, D F A, and diminish the fifth, making it d diminished, D F Ab. If you want to work with it from a Major triad though, you'll have to convert it to minor first, which isn't difficult at all haha. With augmented triads, you take D Major, D F# A, and augment the fifth, making it D Augmented, D F# A#. I hope that made sense!