for this song, there is only reallly one riff,
and its not really a riff,
but make sure your volume + distortion on your amp
are up really loud, but turn the volume on your guitar to like 5 or 7

Main Riff

|---------|
|---------|
|---------|
|-3-3-3-3-|  for this use,the pick patterns, up down up down
|-3-3-3-3-|
|-1-1-1-1-|

Pm--------|


to get the feedback noise play this

|----|
|----|
|----|
|-7*-|
|-7*-|
|-5*-|

*- dont play the note, jus put your fingers there
then turn the volume on your guitar up tto make a feedback noise