Intro riff 1:

E|----------------0-----0------------------------------------------------|
B|----------4-----------------4-----4-----4------------------------------|
G|----3------------------------------------------------------------------|
D|-0-----0-----0-----0-----0-----0-----0---------------------------------|
A|-----------------------------------------------------------------------|
E|-----------------------------------------------------------------------|

Repeat X4

Riff 2:

E|-------------------------------------------------------------------------|
B|----------------3-----------------------5--------------------------------|
G|----3-----1--------------------------------------------------------------|
D|----------------------4-----2-----0-----------3-----1--------------------|
A|-4-----4-----4-----4-----4-----4-----4-----4-----4-----------------------|
E|-------------------------------------------------------------------------|

Repeat X3 (staccatto) allowing for a rest of one beat between each riff

Then repeat X3 (legatto) without the rest (ie - keep the riff rolling!)

Then I think the next riff is this.....

E|-----------------------------------------------------------------------|
B|--------------------------1---------3----------------------------------|
G|---------------------1---------3----4----------------------------------|
D|------3---------4------------------------------------------------------|
A|-4---------2-----------------------------------------------------------|
E|-----------------------------------------------------------------------|