piano chord
G♭m9
G♭1B♭♭♭3D♭5F♭♭7A♭9
A minor seventh with a ninth on top.
Written the other way round it is F♯m9 — the same twelve keys on a piano, a different piece of notation.
What is true of it
G♭m9 is G♭, B♭♭, D♭, F♭ and A♭ — 1, b3, 5, b7 and 9 counted from G♭.
B♭♭ is a double flat, and it has to be: every letter from G♭ upwards is used once, so the b3 cannot be written any other way.
On an instrument that cannot reach all 5, the 5 and 1 go first, in that order.