At the end of the enrollment period for students, courses and classes are no longer listed current for teachers. This means that on their main Schoolnet page, the sections for the previous semester or year are not listed. However, they can still get to all data for students they have taught previously by using the Reports or Classroom Student Performance menus. Step by step instructions are attached in a pdf format.
There is also a quick reference card for finding past year and section data posted at: https://ecsd.zendesk.com/hc/en-us/articles/215787963-Schoolnet-Quick-Reference-Card-Viewing-Data-for-Past-Year-Semester-Students