Intro
Palm mute the first note to keep the note from ringing. Play the natural harmonic (N.H) on the 5th fret with your 1st finger and the natural harmonic on the 7th fret with your 3rd finger:
Natural harmonics can be played by barely touching the string right above the fret and then picking the note. See the video below:
Here is the entire riff with the fingerings:
Now practice playing the riff one note at a time:
Once you get more comfortable with the note pattern, try playing it along with a metronome at a slow speed:
Here’s a video of the entire riff being played: