What is true of it
G♭dim7 is G♭, B♭♭, D♭♭ and F♭♭ — 1, b3, b5 and bb7 counted from G♭.
B♭♭, D♭♭ and F♭♭ 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.
The easiest of the 1 fingering below is bcbc: 3 fingers, one of them barring the 11th fret, 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♭dim7/B♭♭
2323
G♭dim7/D♭♭
5320
G♭dim7/F♭♭
8989
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.