We're going to discover 7th chords in the key of C. You would think we would play C7th in the key of C however the most popular cadences actually contain the 7th of the fith chord, wow that sounds complicated! Just look at it this way; the 5th chord in the key of C is G which we already learned, now just add the 7th note from G back to the chord which is going to be the F note. You can play every note you would normally play in the G chord and just add an F too.
You can play inversion of 7th chords as well as roots, I showed both in the video.
Later in the video does show the C7th Major and dominent. You will play a regular or inverted C and just add the B note because that is the 7th note if we count up from C.
To create a dominent C7 we will lower that B by a half step so now you will be playing a B flat, How Jazzy!
Skip to the end of the video to see an example of all these chords in action.