To start learning 張學友 - 情書 chords, centre your learning around these elemetal chords sequence: G, Em, C, D, G, Bm, C, G and C. To build a solid grasp, start slowly at 51 BPM and then match the original tempo of 103 BPM. Considering your vocal pitch and chord choices, adjust the capo in accordance with the key: Ab Major.