Complex sentence: Students signed a petition during lunch, wrote letters to the Superintendent of the district and other members of the school board, and over 200 students participated in a walk-out for an hour to show their support for their teachers.
Split into simpler sentences: Students signed a petition during lunch, wrote letters to the Superintendent of the district and other members of the school board. Additionally, over 200 students participated in a walk-out for an hour to show their support for their teachers.