The melody of River by Josh Groban runs 434 notes across 72 bars, 3:58 long in Db at 75 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? River chords and lyrics.