It start the bass part with a slide:

E --12/----- 

This is the whole song until the end :

G ----------------------------------------------------------------- 
D ----------------------------------------------------------------- 
A -----------------3-3-3-3-3-3-5-3--------------------------------- 
E -0-0-0-0-0-0-3-0-----------------3-3-3-3-3-3-5-3-2-2-2-2-2-2-3-2- 

When the song is almost ending , the bass change like this :

G ------------------------------------- 
D ------------------------------------- 
A -----------------3-3-3-3-3-3-5-3----- 
E -0-0-0-0-0-0-3-0------------------5-3