To learn 許冠傑 - 天才白癡夢 chords, anchor your practice on these foundational sequence of chords - Gb, Abm, Db, Ebm, Ab, Ebm and Abm. I suggest starting at a calm pace of 57 BPM, and as you gain confidence, approach the song's BPM of 114. Align the capo with your vocal depth and chord choice, bearing in mind the song's original key: Gb Major.