The riff is basically this all the way through:

Bb5 Bb5 G5 F5 Eb5 D5 F5

I'd tend to suggest playing it higher up like so, at least at the start:

e | ------------------------------4-----1-------------- | 
B | ----6-----6-----3-----1-----5--5---3--3-----1------ | 
G | ---7--7--7--7--3--3--2--2--4-----2----------2------ | 
D | -8-----7-----5-----3-----3-------------3----------- | 
A | --------------------------------------------------- | 
E | --------------------------------------------------- | 

                       Bb5  Bb5 G5  F5 Eb5 D5 F5
There was a day in the Grave   yard
                      Bb5   
With helicopters overhead,
Bb5    G5         F5  
I had a rose petal bed,
         Eb5 D5         F5
I had the    sun on my shoes,
   Bb5 Bb5 G5 F5    Eb5   D5         F5
And I knew, I knew, yeah I could see
        Bb5       Bb5    G5           F5  
That if you could make another one of you,
     Eb5           D5       F5
Then you wouldn't give the other one to me, oh no
  Bb5        Bb5    G5           F5
If you could make another one of you,
    Eb5            D5       F5
Then you wouldn't give the other one to me.

Bb5 Bb5       G5     F5   
    If the conductor fucks up,
   Eb5 D5              F5            Bb5
You   can't blame the symphony, so
Bb5   G5     F5      Eb5    
I won't blame you if you, 
   D5        F5
if you don't blame me,

Bb5 Bb5 G5 F5 Eb5 D5 F5
                   You were doing something else that day x4

*humming* (repeat until end)