Tuning: u can tune it how ever u wont to but I prefer to down tune the whole guitar 1 step 

Riff a  |-------------------------------------------------------
        |-------------------------------------------------------
        |-----0------------------0------------------------------
        |-------2-0------0-2-------0-2-----------2------2-------
        |-------------------------------------------------------
        |0------------3----------------------0------00----------

Riff b  |-------------------------------------------------------
        |-------------------------------------------------------
        |-----0------------------0------------------------------
        |-------2-0------0-2-------0-2-----------2------4-------
        |-------------------------------------------------------
        |0------------3----------------------0------00----------

Riff c  |-------------------------------------------------------
        |-------------------------------------------------------
        |-----0------------------0------------------------------
        |-------2-0------0-2-------0-2-----------2------0-------
        |-------------------------------------------------------
        |0------------3----------------------0------00----------

Riff d  |-------------------------------------------------------
        |-------------------------------------------------------
        |-----0------------------0------------------------0-----
        |-------2-0------0-2-------0-2-----------2----------4---
        |-------------------------------------------------------
        |0------------3----------------------0------00----------


Song goes                   
Riff a 
Riff b
Riff c
Riff a
Riff b
Riff a
Riff d
Riff a

And then it goes
Riff a 
Riff b
Riff c
Riff a
Riff b
Riff a
Riff d