Watch the Half-Steppin' online guitar lesson by Brad Carlton from Chord Studies: Flamenco Chords Vol. 2
This group of flamenco chords starts with an A11b9. You could play this first chord with various fingerings, but pay attention to the economy of motion as you move your 2nd and 3rd voices down a half step. The A5 surrounds both of these voices creating that great flamenco flavor. Be careful to bring your wrist forward and arch the fingers of your fretting hand to get a clean voicing.