The main riff
Standard tuning

-----------------|
-----------------|
-666-----999-----|
-666-999-9997-77-|
-444-997-7777-77-|
-----777----5-55-|

-----------------|
-----------------|
-666-----999-----|
-666-999-9997-77-|
-444-997-7777-77-|
-----777----5-55-|

-----------------|
-----------------|
-666-----999-----|
-666-999-9997-77-|
-444-997-7777-77-|
-----777----5-55-|

Just repeat it throughout the song.