To start learning Os Arrais - Rojões chords, build your understanding on these basic chords - Bb, Ab, Gm, Bb, Ab, Cm and Bb in sequence. I suggest starting at a calm pace of 66 BPM, and as you gain confidence, approach the song's BPM of 132. Considering the song's key of Bb Major, position your capo to suit your vocal and chord preferences.