To learn B.B. King - Back Door Santa chords, these are the chords to practise in sequence: Bbm, Eb, Ab, Bbm, Fm, Gb, Eb, Gb, Ab and Ebm. I suggest starting at a calm pace of 56 BPM, and as you gain confidence, approach the song's BPM of 113. Considering your vocal pitch and chord choices, adjust the capo in accordance with the key: Eb Major.