The bass part comes in after the small guitar intro.

INTRO/VERSE/OUTRO 

G|---------------------------------------------------------------------
D|----------------------------9-10-0-0-0-0-0-0-5-7---------------------
A|0-0-0-0-0-0-5-7-8-8-8-8-8-8----------------------7-7-7-7-7-7-3-2-----
E|---------------------------------------------------------------------

PRECHORUS

G|--------------------------------  This is the 'buildup' if you like...
D|--------0-----0-2---0-2-3-0-2-3-
A|3-0-2-3---2-3-----3-------------
E|--------------------------------

G|2-------2-------1---------------
D|--3-2-3---3-2-3---3-2-3--3--3---  This bit is a little quicker.  
A|--------------------------------  Listen to the song for the exact timing.
E|--------------------------------  

CHORUS

G|-----------------------------------
D|------33------22------22------33--- 
A|-3-3-3---3-3-3---0-0-0---0-0-0-----
E|-----------------------------------

INTRO/VERSE/OUTRO: X3
PRECHORUS: X1
CHORUS: X3
INTRO/VERSE/OUTRO: X3
PRECHORUS: X1
CHORUS: X3

INTRO/VERSE/OUTRO: X2