The melody of The Boy Is Mine by Brandy & Monica runs 458 notes across 51 bars, 3:17 long in C#m at 100 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? The Boy Is Mine chords and lyrics.