To jam and learn S.A. Karl - Castor chords, your primary focus should be mastering these chords sequence: C, Cm, Bb, Eb, Cm, Dm, Bb, F, Eb and Cm. For a smooth transition, initiate your practice at 67 BPM and gradually match the song's pace of 136 BPM. Align the capo with your vocal depth and chord choice, bearing in mind the song's original key: Bb Major.