As an Admin, via your admin dashboard, you have access to editing classroom name, school, teacher, and co-teacher. You may be looking to add a teacher for the first time or to switch classroom ownership between existing teachers.
Follow these 5 steps to do so from the Admin dashboard:
From the main menu, choose Admin Dashboard
Go to the Teachers tab
On the right hand, above the teacher list, you will see a text box and a green button that says "Invite Teacher"
Enter the teacher's email address, which will be used as the login email (usually a school email or a work email)
Click the "Invite teacher" button. The teacher will now receive an invitation to create their account.
The teacher will be added to the Admin list of invited teachers and will have a "pending" status. Once the teacher approves the invitation and creates an account, the status will change from "Pending" to "Active".