Hi @jbest,
I’m pretty sure there’s no way to merge accounts. I recommend having the student pick whichever account they prefer to use, then have that account join your section using that section’s enrollment code.
Creating an account and adding the account to a section are two separate things. When you “added all the students into sections by classes”, I’m guessing you had them directly add themselves to a section - when students try to do this without an account, the website will prompt them to create an account (or if they have an existing account, they can just login with that account) then they will be added to the section.
As a teacher managing the sections, you can remove a student’s account from your section, but as far as I know, you’re not deleting their account. They can still use the enrollment code to re-enroll, but I’m not sure what happens to their progress, whether it’s saved or it was permanently deleted when they un-enrolled.
If you are still having difficulty, feel free to follow up here or email support@code.org.
Frank