GUEST,Michael,

The accompaniment here uses basically the harmonies of I and V chords, for example C and G chords if you're in the key of C, or D and A chords if you're in the key of D. It would be much faster just to figure out where those chords fall, by trial and error, than for me to attempt to specify in a post.

Sometimes, at the end of each verse, they throw in the IV chord as a surprise, i.e. an F chord (if you're in the key of C). And sometimes they even throw in an A minor chord at the end of each second solo line.

If you play in key of C, then your chords in the mix will therefore be C, G, F, and A minor. Play around with these 4 and you'll get it.

https://youtu.be/JNEgaXbQAGw