Its a very simple song. His chord prgression is repetitive. if you are learning 
how to do bar chords its a song for you. 

the chord progression is as follows.

D, F# , G*, F#.

for the chorus all you have to do is release the bar on the bottom 2 strings when 
you play the G and the F#.

chorus progression is

G*, F# repeat as needed

D- 2320xx F#-223442 G*- 334553

the chorus chords

G*- 004553 F#- 003442