The chord Gbm6 that is shown here contains the notes: Gb, A, Eb. The root of the chord is Gb (The lowest sound - the bass - is GB). The scale from which the chord is derived is Minor sixth chord (1–♭3–5–6), and the degrees of the scale are: 1, ♭3, 5, 6.
To play the chord Gbm6 shown above, place your fingers as follows:
On string number 4, on fret number 4
On string number 3, on fret number 2
On string number 2, on fret number 4
On string number 1 (the thinnest), on fret number 2
Start strumming from string number 4 (notice not to play strings 5 and 6).