First tab :)
The whole song is basically D A Bm G
But here's an example of when to change.
For the rest of the verses just listen to the song and you'll pick it up pretty easy :)

D                                   A
I'll put a message in a bottle and I'll throw it across the sea
Bm              G
Your the lock and included is the key
D                   A
Along with a dozen x's and o's
Bm              G
Lord knows that you can't get enough of those
D                         A
Your superkalafragelisticexpialadociously cute
Bm           G
Sweeter than a 12 pack of juicy fruit
D                A
Surreal, but I know this isn't a dream
Bm               G
We go good together just like coffee and cream