Complex sentence: She created a four years training system for nurses-to-be, after the first year they were required to take an exam on all of the information they had learned, and if they passed if they could become probationers.
Split into simpler sentences: She created a four years training system for nurses-to-be. After the first year they were required to take an exam on all of the information they had learned, and if they passed if they could become probationers.