1.
Place your index finger over all six strings at the 5th fret and press down. Strum a few times to make sure each note rings clear. This is the ‘barre’ part of the chord, and is universal to barre chords.
2.
Protect the 7th fret on the 6th string with your ring finger. Strum again and make sure the notes are still clear.
3.
Thread the fifth string with the fifth string with your little finger. Strum once more. This is a A minor bar chord. If you look closely, you will see that the shape is similar to E’s less open chord shape with the finger as the guitar nut.
To make other barre chords, simply mimicking open chord shapes, replace your index finger as the nut. Remember that the root note makes the chord. For example, the root of the A minor chord A at the 6th string is the 5th fret. If you used an open A minor form as a bar chord and played it at the 5th fret, it would be a D-minor, since the root is the 5th string, the 5th fret.
Tips and warnings
Barre chords (sometimes called just bar chords) are a key technique for every guitarist. By foaming all the strings over a single finger with one finger, you can use open chord shapes the entire length of the neck, open up many recording options, and enable the integration of chords and scale patterns. For this example, you play a small chord at the 5th fret. To use barre chords effectively, you should have a good knowledge of open guitar chord shapes.
Source:danspela.com