Intro:
E|-------------------------------------------------------| |
B|-------------------------------------------------------| |
G|------------------------------------------------------o| |
D|------------------------------------------------------o| |
A|2-x-22-x-2-/-5-x-55-x-5---2-x-22-x-2-/-5-x-55----------| |
E|-----------------------3-5-------------------3-5-6-----| |
  .    .       .    .  . .. .    .        .  . . .

Riff 1 (when the vocals begin)
                          ending A)
E|------------------------|---------------------| |
B|------------------------|---------------------| |
G|------------------------|---------------------| |
D|------------------------|---------------------| |
A|2-x-22-x-2-/-5-x-55-x-5-|---------------------| |
E|------------------------| 6-x-66-x-66-x-66-x-6-||
  .    .       .    .      .    .    .    .
 ending B)
E|---------------------| |
B|---------------------| |
G|---------------------| | (also gtr.2)
D|4-x-44-x-4-----------| |
A|---------------------| |
E|----------6-x-66-x-6-| |
   .    .    .    .

Riff 2 (main riff)
E|--------------------------------------------| |
B|--------------------------------------------| |
G|-------------------------------------------o| |
D|-------------------------------------------o| |
A|--------------------------------------------| |
6"-5--3-3h5p3-3-3--3-6"-5--3-2h3p2-2-2------||
      .       .    .       .       .

Riff 3          ending A) (I think 4x)
E|--------------|------------------| |
B|--------------|------------------| |
G|--------------|------------------| |
D|--------------|------------------| |
A|2-x-7---------|------------------| |
E|-----6--0-3-5-|-0-0-0-0-0-0-0-0--| |
  .     .       . . . . . . . .

Ending B)
E|----------------------| |
B|----------------------| |
G|----------------------| |
D|----------------------| |
A|2"--1"--2"-4"---------| |
E|----------------------| |