Here is the strumming pattern:
o=play
x=mute
↓=strum downward
↑=strum upward
they're broken into sixteenths
↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑↓↑ (8 beats)
OxxxOxxOxxxxxxxOxoxOOxOxOxxxxxxx(repeat)
For those who can subdivide think these in your head:
1e+a2e+a3e+a4e+a1e+a2e+a3e+a4e+a

CHORDS:

Intro:
E    F#    E    F#(6x)

Verse:
E    F#    E    F#(4x)

Pre-Chorus:
A	Ab	C#m	F#
F#m	Ab

Chorus:
E    F#    E    F#(3x)
Ab

Instrumental:
E    F#    E    F#(2x)

Verse:
E    F#    E    F#(4x)

Pre-Chorus:
A	Ab	C#m	F#
F#m	Ab

Chorus:
E    F#    E    F#(3x)
Ab (repeat Chorus)

Instrumental:
G#m muted for 16 measures then
E    F#    E    F#(4x)

Pre-Chorus:
A	Ab	C#m	F#
F#m	Ab

Chorus:
E    F#    E    F#(3x)
Ab (repeat Chorus)

Ending:
Ab