This is the main guitar riff which appears as
the intro and in various places thoughout
the song.

E5 (heavily palm muted) repeated using downstrokes
then

A A Ab A Ab  
G G Gb G Gb   
F F F F F F G  G G E5

B B Bb B Bb  
A A Ab A Ab   
G G G G G G G  A A  E5

use barre chords.

then everything goes a bit mad!!!

if you can't get the rhythm correct try thinking
of the theme tune to "Steptoe and son" because
it's almost the same..