I think the strum pattern for the intro is just up/down. Strumming for the rest of the
repeats the D#m and G#m chords and has a very reggae feel so just listen to it for a
idea. Enjoy!
[ Tab from: http://www.guitaretab.com/n/nneka/230039.html ]
D#m G#m C#
e|----6------|----------------|----4------|-----4-----|
B|----7------|--7p6----6h7/9--|----4------|-----6-----|
G|----8------|-------6--------|----4------|-----6-----|
D|----8------|----------------|----6------|-----6-----|
A|----6------|----------------|----6------|-----4-----|
E|----0------|----------------|----4------|-----0-----|