Complex sentence: She showed an interest in pop and rock music during her years at Besiktas Ataturk High School, Culminated in a third place finish in a Song Contest among high-school students in Turkey.
Split into simpler sentences: She showed an interest in pop and rock music during her schooling years at Besiktas Ataturk High School. This culminated in a third place finish in a Song Contest among high-schoolers in Turkey.