After watching this one, I finally understand diminished and augmented chords.. well the basics.
there is the starter video. He seems to have designed the series to build of the previous video.
Not looking for theory snobs to rip him to shreds because this isn't training you for a college degree in composition. But it seems to be super handy for quite a number of people (judging from the likes) including ME who just want to learn a bit more.