So now that we have built a Major triad and Major7th chord. Lets make a minor chord!
The process of building minor chords is exactly the same, bar one thing.
If the chord is a 'minor triad' (meaning it has 3 notes) we must make sure that the 3rd is minor. If the Chord is going to be a 'minor 7th' we will have to give it a minor 3rd & a minor 7th.
So like before, if we count up the C Major scale and skip every second note we wind up with these notes.
C D E F G A B C
C E G B
So far we have a Major 7th chord.
To make this a minor 7th. The 3rd and 7th need to be lowered by 1 semi tone each.
This means that 'E' the 3rd needs to become 'Eb' and 'B' the 7th needs to become 'Bb'. Ultimately leaving us with these 4 notes. C Eb G Bb
Below are some examples in tab and standard notation for your reference and analysis.