Help deciphering arpeggios in song
 

Hi, I'm new here and I hope this is the correct place to post this. I'm playing the song step by Vampire weekend with a band and I'm having trouble deciphering the arpeggios played in the opening. I'm not sure when they change or how long they're played for. The piano tab is available if you Google it it's on 991tabs sorry I can't post it. Please help, thanks in advance!