With these backing blues tracks, you can learn how to play the alto saxophone blues. The play along blues tracks for alto sax will help you develop a feel the blues changes over time.  The chords for this alto saxophone blues track are:
In the 12 Bar Blues, the 1 Chord is ‘F Chord’ - Notes F, A, C
In the 12 Bar Blues, the 4 Chord is ‘Bb Chord’ - Notes Bb, D, F
In the 12 Bar Blues, the 5 Chord is ‘C Chord’ - Notes C, E, G
Some MAGIC notes to play around with are D, F, G