The eight science and engineering practices outlined in the Next Generation Science Standards (NGSS) are key to student science learning. However, there is limited guidance for teachers on what these practices "look like" in instruction across different grade ranges and topic areas. Further, there is little existing guidance for teachers on how to make the practices in the NGSS accessible to all students, particularly those from groups that have traditionally been underserved in science education. This paper describes the development of a primer that operationalizes the science practices for different grade levels and content areas. This work is part of a larger study aimed at developing survey items to measure teachers' use of the science practices.