The melody of O by Coldplay runs 160 notes across 29 bars, 3:42 long in Eb at 68 beats per minute. The tab sits low on the neck, mostly under the fourth fret, one note at a time — no chords to barre and no strumming pattern to keep up with. A piano backing track plays the chords and bass underneath, so the line you are learning sounds like the record even at half speed.
Prefer to strum and sing it instead? O chords and lyrics.