Controlling settings, permissions, and membership within Teams and channels
Hi Angie,
As per your description, you can add students to a class team you've already created via click into that team and select “…” next to it -> Add members -> under student tab, input address of each student.
Here’s an official article for your reference: Add a student to a class team.
Another workaround to add students via Office 365 group management page. Let your admin go to Microsoft 365 Admin Center > Groups > find the related Class Team group > click the group > Members > View all and manage members > Add members.
As you mention “I'm trying to add my students to my Team but they are not recognized” could you please provide us some related screenshot for better understand.
I appreciate your patience and understanding.
Best Regards
Waqas Muhammad