What is true of it
G♭m7♭5 is G♭, B♭♭, D♭♭ and F♭ — 1, b3, b5 and b7 counted from G♭.
B♭♭ and D♭♭ are double flats, and they have to be: every letter from G♭ upwards is used once, so the b3 cannot be written any other way.
These are also the notes of Am6/G♭. Which name is right depends on what is underneath and what came before — the notes alone do not decide.
The easiest of the 1 fingering below is bccc: 4 fingers, held at the 11th fret.
None of them uses an open string, so this chord moves up the neck unchanged — the same shape 1 fret higher is the chord a semitone above.
Where its notes are on the neck
The brass dots are G♭, the root. Everything else is a chord tone with its degree printed in it.
With a different note underneath
G♭m7♭5/B♭♭
2423
G♭m7♭5/D♭♭
5420
G♭m7♭5/F♭
9989
An inversion is the same chord with a different note lowest. The name changes to a slash name because the bass is what a listener hears as the foundation.