This song is played tuned down 1/2 step:

For the intro and verses he slides between these partial chords...

C - x32xxx   Em - x75xxx   G - x(10)9xxx

Then when G/B-G/D is played, he does this...

C - x32xxx   Em - x75xxx   G - x(10)9xxx  G/B - 7(10)9xxx  G/D - (10)(10)9xxx

That`s played for both the intro and the first 2 lines of the verse.
You hold out the chords twice as long in the verses.
Just listen for the Timing. Here`s the rest of the song:


Intro:     C   Em   G
           C   Em   G  G/B-G/D
           C   Em   G  G/B-G/D
           C   Em   G

Verse 1:   C   Em   G  G/B-G/D
           C   Em   G  G/B-G/D
           F   C/E  C  G/B

Chorus 1:  F   G   F   G
           F   G

Verse 2:   C   Em   G   G/B-G/D
           C   Em   G   G/B-G/D
           F   C/E  C   G/B   G/B

Chorus 2:  F    G    F    G
           F    G    F    G 
           F    G    F/A  G/B

Bridge:    F   C/E   C   G/B  (x2 instrumentally)
           
           F   C/E   C   G/B
           F   C/E   C   G/B
           F   C/E   C   G/B  G/B

Chorus 3:  F    G    F    G
           F    G    F    G
           F    G    F    G    F/A  G/B
           F    G    F/A  G/B
           F    G    F/A  G/B  

Ending:    C   Em   G  (x4)