The melody of What Now by Rihanna runs 418 notes across 43 bars, 3:52 long in Am at 93 beats per minute. The tab sits moving up the neck in places, 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? What Now chords and lyrics.