This is the Bass line of the first part of the song :
that's the main thing (from 0:06 to 0:30) :
G|--------------------|
D|--------------------|
A|--------------------|
D|-88--877--755--577--|

Then there's a little variation at 0:24 :
G|--------------------|
D|--------------------|
A|--------------------|
D|-88--877--7h88--877-|