Notes: Unless you use a 5 string, Drop the E to around a D for it to sound better..

Basically repeat this through-out the whole song after letting the guitar do the intro...

G|----------------------------------------|
D|----------------------------------------|
A|----------------------------------------|
D|-1-1--1-1--1-1--1-1--3-3--3-3--3-3--3-3-|

Plus: 
At the ending of the chorus you need to play
|-1-1--1-1--1-1--1~-|

then back to 
|-1-1--1-1--1-1--1-1--3-3--3-3--3-3--3-3-| etc.

That's the basics, play around with it if you want and put your own spin on it.