The melody of Rejoice by Katherine Jenkins runs 225 notes across 44 bars, 3:04 long in Gb at 60 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? Rejoice chords and lyrics.