Alrighty then! Now that you have watched the full video, very carefully I might add, we can get to work breaking those riffs down so that we can totally nail them.
The opening riff alternates using the open, in this case, low D string with various fretted notes using downpicking only. This helps to emphasise the alternation of open versus fretted strings. In the score, I decided not to indicate a key signature as it I feel it is easier to digest the information through individual notes.
This riff has two distinct parts which are 4 bars in duration. The rhythm in each part is identical but the notes do differ slightly so please give each part your full attention. For the left hand, use whatever fingering you are comfortable with. Feel free to use mine or, even better, come up with your own. OK, riff 2 awaits us!