The melody of I Want by One Direction runs 350 notes across 55 bars, 2:38 long in Am at 128 beats per minute. The tab sits almost entirely in the first two frets, 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? I Want chords and lyrics.