it's a simple 4 chord song.
listen to the song to get the stumming. 
it's pretty easy.

Dm :xx0231
Bb :x13300
F  :133211
C  :x32010


Intro: Dm Bb F C (4x)


Verse 1:
Dm       Bb         F           C 
Amazing Grace, how sweet the sound
Dm       Bb         F    C
that saved a wretch like me
Dm          Bb      F           C
I once was lost but now i'm found
Dm       Bb     F         C
was blind but, now i see so clearly

Chorus:
Dm          Bb               F           C
     Hallelujah, Grace like rain falls down on me
Dm          Bb               F              C
     Hallelujah, All my stains are washed away 
Dm          Bb               F           C
     Hallelujah, Grace like rain falls down on me
Dm          Bb               F              C          Dm
     Hallelujah, All my stains are washed away, washed away

(From the last Dm on the chorus go to the inro and do it 2x before you go on to verse 2)

Verse 2:
(same chords as verse 1)
'Twas grace that taught my heart to fear
and grace my fears relieved
how precious did that grace appear
the hour I first believed.

(chorus 2x)