This song maintains the same pattern throught.
The song starts with the bass playing D(5th fret,Ab string)during the desending note run.Just let it ring.
Then play this in unison with the guitars:

Gb{                                                                                            }
Db{                3..                  3..                  3..                            }
Ab{....3..33..5    5———..333..5    5———..333..5    5———..33..5..3..0———}
Eb{                                                                                            }

Drop out until the end of the 1st chorus.
When you comeback in(during the desending note run),play a D again.
Then:

Gb{                                                     }
Db{                         3..3.                     }
Ab{...........5..5.              5———.3..3.       }
Eb{                  3———.                     3———.}

during the 2nd and 3rd verse,end the riff like this:

Gb{                                                     }
Db{                                                     }
Ab{......5..3..0————................................}
Eb{                                                     }

during the chorus,end it with this:

Gb{                                                                               }
Db{          3..                                       3..                      }
Ab{..3..5..     5———.....3..3..        ...3..5..    5————...............}
Eb{                                  3———..                                     }

during the outro chorus,end with this:

Gb{                                                                                }
Db{          3..                  3..5..3..                  3..              }
Ab{..3..5..    5———....3..5..            5———....3..5..     5————————}
Eb{                                                                                }

Finally,during the desending note run play the D again.
p.s.:If your bass doesn't have good sustain,or your noisegate is
killing your signal too early,try hitting the open D(on the D string)
with the D at the 5th fret of the A string.These double stops ring
louder.
hope you enjoyed playin!!!!!!