To learn 光良 - 約定 chords, your first step should be understanding these chords - Dm, C, F, C, F, Bb, Eb, Bb, Cm, Gm and Bb in sequence. For a smooth transition, initiate your practice at 48 BPM and gradually match the song's pace of 96 BPM. With Bb Major as the song's key, tweak the capo to cater to your vocal pitch and chord likes.