Most of the palm mutes in here are more like quick pause to get the struming correct. 
to explain, listen to the song.

p - pull off
. - palm mute
/ - slide

Full Step Down
Intro x1
D|-----|
A|-----|
F|-/9--|
C|-/9--| Pickslide
G|-/7--|
D|-----|


Verse x4
D|-------------------------------------------------|
A|-------------------------------------------------|
F|-------------------------------------------------|
C|-2-2-2-5p2-2-2-2---2-2-2h5-5-5-5--5-5-5/8-8-8-8--|
G|-2-2-2-5p2-2-2-2---2-2-2h5-5-5-5--5-5-5/8-8-8-8--|
D|-0-0-0-3p0-0-0-0---0-0-0h3-3-3-3--3-3-3/6-6-6-6--|


Chorus x2
D|--------------------------------------------|
A|--------------------------------------------|
F|--------------------------------------------|
C|-2-5--2-8--2-5--2-2-2-2-2-2-2--5-5-5-8-8-8--|
G|-2-5--2-8--2-5--2-2-2-2-2-2-2--5-5-5-8-8-8--|
D|-0-3--0-6--0-3--0-0-0-0-0-0-0--3-3-3-6-6-6--|


Verse x2
D|--------------------------------|
A|--------------------------------|
F|--------------------------------|
C|-8-7-5--8-7-5--2---5---8-8-8-8--|
G|-8-7-5--8-7-5--2---5---8-8-8-8--|
D|-6-5-3--6-5-3--0-0-3-3-6-6-6-6--|
                   .   .


Chorus x2
D|--------------------------------------------|
A|--------------------------------------------|
F|--------------------------------------------|
C|-2-5--2-8--2-5--2-2-2-2-2-2-2--5-5-5-8-8-8--|
G|-2-5--2-8--2-5--2-2-2-2-2-2-2--5-5-5-8-8-8--|
D|-0-3--0-6--0-3--0-0-0-0-0-0-0--3-3-3-6-6-6--|

Verse x1
D|------------------|
A|------------------|
F|------------------|
C|-8-7-5--8-7-5--2--|
G|-8-7-5--8-7-5--2--|
D|-6-5-3--6-5-3--0--|


Breakdown x3 (2nd guitar plays same chords, but only strums them once the first time)
D|-----------------------------------------------------------------------|
A|-----------------------------------------------------------------------|
F|-----------------------------------------------------------------------|
C|-2-2-2-2-2-2-2-2--5-5-5-5--8-8-8-8--2-2-2-2-2-2-2-2--5-5-5-5--3-3-3-3--|
G|-2-2-2-2-2-2-2-2--5-5-5-5--8-8-8-8--2-2-2-2-2-2-2-2--5-5-5-5--3-3-3-3--|
D|-0-0-0-0-0-0-0-0--3-3-3-3--6-6-6-6--0-0-0-0-0-0-0-0--3-3-3-3--1-1-1-1--|