Complex sentence: The brothers were supporters of the Selangor team and so decided to write a rap tune for their favourite team back then they were known as Selangor Rappers' Unit, writing "Viva Selangor".
Split into simpler sentences: The brothers were supporters of the Selangor team and also decided to write a rap tune for their favourite team. Back then they were known as Selangor Rappers' Unit, writing "Viva Selangor".