To learn 李克勤 - 舊歡如夢 chords, grasp the musical fabric of the song with this sequence - Dm, A, Dm, Gm, Dm, C, Dm, Gm and A of chords. I suggest starting at a calm pace of 57 BPM, and as you gain confidence, approach the song's BPM of 115. Adjust the capo based on your vocal range and chord preference, keeping the song's key of D Minor in mind.