This Song is easy ............
all u need to do is just put the D chord in Seventh fret and then move your little finger up and down LIKE THIS :

-----7---------              -----8---------
-----8---------              -----8----------
-----7---------              -----7----------
---------------              ---------------
---------------              ---------------
---------------              ---------------

easy huh !!!! and then let the BASS do their jobs

THAT's ALL UNTIL THE END OF THE SONG