Just as major chords, minor chords consist of three notes stacked upon one another. You can create it by playing the root, adding the minor third, and the fifth.
In the key of C, these would be C, Eb and G. So The notes are almost the same as those of the C major chord. You only have to move the major third E down a half step to the minor third Eb.
And this is the formula to create all minor chords.
If you know the respective major chord, just move the major third down a half step to the minor third.
Another way to arrive at minor chords is by counting the half steps. The minor third is 3 half steps up from the root. The fifth is another 4 half steps (or the interval of a major third) up. So you just need to remember two numbers:
4 + 3 halfsteps
to create a minor chord in any key.
Note that the numbers are just the other way around from those for major chords!
If you take another starting point – say, G – you will arrive at the minor third Bb by counting 3 half steps up. The fifth, D, is another three half steps up from Bb.
The fingering for all minor chords is the same as for major chords
1 – 3 – 5 in the right hand, and
5 – 3 – 1 in the left hand.