What is true of it
A♯m7♭5 is A♯, C♯, E and G♯ — 1, b3, b5 and b7 counted from A♯.
These are also the notes of C♯m6/A♯ and D♭m6/A♯. 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 3444: 4 fingers, held at the 3rd 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 A♯, the root. Everything else is a chord tone with its degree printed in it.
With a different note underneath
A♯m7♭5/C♯
6867
A♯m7♭5/E
9a9b
A♯m7♭5/G♯
1101
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.