Chan Chan was originally written by Compay Segundo. But it’s the Buena Vista Social Club version that is best known. And it’s that one I worked from.
Intro: The intro sets up the chord progression that’s used (adding a 6 or 7 here and there) all the way through the song: Dm-F-Gm-A. The rest of the song is in 4 bar sections, but the intro has 6 bars. Which makes the start of the verse come in at an odd place.
Verses: For the melody sections, you’re playing the same chords at the fifth fret. And that’s interspersed with two bars from the intro.
Chorus: A very similar melody to the verse, but this time played twice through and with a four bar section of the intro.