Alright I hate it when the say punk is all power chords.
So I'll explain it best i understand.
A power chord is just a barred E, so if you keep your bar like a power chord, your index finger,
change the positions of your other finger to make other chordswith the bar, index finger, still there. Practice.
Now Palm Muting, change through the chords, try to follow the theory of Uh the path the chords follow if you know it,
if not, Just try like E C G D A E or whatever backwards and forwards and backwards and forwards While Barred with index
on diffent frets moving up and down the Neck.
Well Try that If not F*ck you too haha