The hammer on's in this song go as follows:
    G        C        D
E|--------------------0h2--|
B|-----------1--------3----|
G|--0--------0--------2----|
D|--0--------0h2------0----|
A|--0h2------3-------------|
E|--3----------------------|

With a strumming pattern of, UP C WN PAUSE MUTE (down strum mute), (with the hammer-on also on the 'C WN' strum)
Repeat this in the verses.
A simpler strum in the chorus of which you'll just have to work out but with no hammer on's.

Intro: G

G     
The day we met my life was changed
C                                        G
I always heard that love was strange and painful
D
painful
G
One night you slept upon your side
C                                        G
Tangled in white you looked just like an angel
D
angel


   C G         D   Em
So why did you fly away
          C              G                D    Em
I’ve been dying a little death since that very day
          C   G          D    Em
I used to laugh when you told me
         C          G             C
You must forget and forgive to be free


G
Down by the water dressed in black
C                               G
I swore revenge to get you back hateful 
D
hateful
G
I made my camp upon the hill
C                                  G
Drank whisky from the secret still blameful 
D
blameful


   C G         D   Em
So why did you fly away 
          C              G                D    Em
i’ve been dying a little death since that very day
          C   G          D    Em
i used to laugh when you told me
         C          G             C           G
you must forget and forgive to be free

      G     D      A7
And I never could admit
    G      D      A7
the part I had in it
   G       D      A7     Am7
So this is what I get my friend 

G
Drunk in a field with scarlet snow
C                               G
I reconciled with your ghost in April
D
In April
G
I stood before the hypocrite 
C                                G
There in the mirror brightly lit shameful
D
shameful

           C G     D   Em
Now I know why you ran away
              C              G                D    Em
And I’ve been dying a little death since that very day
          C   G          D    Em
I used to laugh when you told me
         C          G
you must forget and forgive 
         C                    
You must forgive just to live
         Em         C                       G
you must forget and forgive to be free