all the 0s aswell as 8s get palm muted in both riff, as you can tell from the „P.M.“ standing over them in the tab. You put your palm at the very end (bridge end) of your strings, muting them the entire time (!) while playing it, only lifting your palm to play the other, unmuted notes.
#Spirit crusher by death.
crisp mirage
i would suggest to actually position your palm in such a way that it only touches the E and A string, eliminating the need to lift your palm.