When transitioning from one school year to the next, students should not re-register or create new accounts; they should simply log back into their original accounts with their same usernames and passwords.
Once they log in, they should click on their student profile (look for the silhouette icon in the upper right):
From there, students should enter your new class code and click the "Replace Class" button:
Students can also remove the old class section from their profile by clicking the "X" beside the old class section.