The melody of Knock You Down by Keri Hilson featuring Kanye West & Ne-Yo runs 766 notes across 86 bars, 4:37 long in Eb at 78 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? Knock You Down chords and lyrics.