intro part (where it is strummed up and down, but very lightly.  listen to the song for 
strum pattern)
-0--2-----------|
-3--3-----------|
-4--4-----------|
-4--4-----------|
-2--2-----------|
----------------| x2

verse
---2---------2--------------------|
---3---------3--------------------|
---4---------4--------------------|
---4---------4--------------------|
-2-2-----4-2-2--------------------|
-----2-5--------------------------|

repeat until whenever it does in the song, then play

prechorus
---2--------2-3-0-----------------|
---3--------2-3-0-----------------|
---4--------3-4-1-----------------|
---4--------4-5-2-----------------|
-2-2-----4--4-5-2-----------------|
-----2-5----2-3-0-----------------|
that repeats a couple of times (listen to the song to find out the exact number of 
then it goes into the chorus, which is

chorus
------------------------------------------------------------------|
------------------------------------------------------------------|
------------------------------------------------------------------|
-------------------------------------4-----4---------4-----4------|
-----2-----2---------2-----2-2-4-5-5---5-5---5-4-2-2---2-2---2-0--|
-3-3---3-3---3-2-3-3---3-3----------------------------------------|

repeat that for however long the chorus is, then play

afterchorus
--3----------------2----------|
--3--------7-------3----------|
--4--------7-------4----------|
--5--------7-------4----------|
--5--------5-------2----------|
--3---------------------------|
these chords are G, D, Bm, i just choose to play them as bar chords, play them however 
wish.  repeat this for however long the song does
then go back and play the verse and the prechorus until whenever the song does, then 
the chorus again, just like the song, and for however long the song does, then play the 
again, but this time it's slightly different, it now goes

afterchorus2
--3-----------2----------3------------2------2-2-2-2-2-2-2-2--|
--3-----7-----3----------3-----7------3------3-3-3-3-3-3-3-3--|
--4-----7-----4----------4-----7------4------4-4-4-4-4-4-4-4--|
--5-----7-----4----------5-----7------4------4-4-4-4-4-4-4-4--|
--5-----5-----2--0h2-----5-----5------2--0h2-2-2-2-2-2-2-2-2--|
--3----------------------3------------------------------------|

then it goes back into the chorus, and it almost sounds like there's 2 guitars here, one 
the chords G, D, Bm, and one playing the picking part of the chorus, play whichever you 
it sounds good either way, though i prefer to pick the chorus here

then go back and play the afterchorus again, 3 times, then play

outro
--3--------------------------------------------|
--3------7-----7-----7-----7-------------------|
--4------7-----7-----7-----7-------------------|
--5------7-----7-----7-----7-------------------|
--5------5-----5-----5-----5-------------------|
--3--------------------------------------------|

so the order the song goes in is:

intro
verse
prechorus
chorus
afterchorus
verse
prechorus
chorus
afterchorus2
chorus
afterchorus
outro