The melody of Diamond Girl by Seals & Crofts runs 222 notes across 73 bars, 3:33 long in Am at 132 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? Diamond Girl chords and lyrics.