For this riff, you may want to use your thumb for the “low E” string notes, as it will provide much more ease in playing the riff. The option is still totally up to you though. In this riff, you will be focusing on some palm mutes and a slide, as well as some “vibrato.” Vibrato is when you rapidly shake the string being played with your fret hand as much as possible to produce a wah-like effect. This riff is set to 144 bpm (beats per minute).
Below is the riff slowed down a little to give you some practice:
Here is the riff at normal speed: