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