Complex sentence: Mr. Shabazz had turned his life around following a drug arrest at age 16, joining the nonprofit youth and leadership group "Aspira", where he learned film editing, and began making films about ending gang violence.
Split into simpler sentences: Mr. Shabazz had turned his life around following a drug arrest at age 16. He received training in film editing from a non-profit youth group, "Aspira", and began to make films about ending gang violence.