This section illustrates a cool contrast between a riff being played with tight palm-muted chunk and then the same riff being played with a more open feel. Bars 5 through 8 being the former. Bars 9 through 12 being the latter.
Keep the palm mutes tight! The rests should be blatantly obvious and contrasting with the notes you play.
For the rests, use your fret-hand to gently slap down on the strings to execute the mutes. Pay close attention to my left hand in the video.
Ready for the backing track? On to the next page!