Arrange the classrooms
This is where a classroom is opened, matched to what parents book, staffed, and — once — closed.
Sign in to open it. It is a course admin's console: course admins write the curriculum and arrange who is taught what, and when. Instructors run the classrooms they hold, and find their own rooms on the bench rather than every room here.
Prefer a link by email? The staff door sends one. Same sign-in and same session; it comes back there rather than here.
What is inside
Running a school, as opposed to writing the course.
Open a classroom — against a course, and pinned to a published plan. Dates are not set here: a classroom holds what is taught, and each meeting of it holds when.
Match it to what parents book — the one setting that connects a booking to a classroom. Until it is made, bookings for that service have nowhere to land and the classroom takes no children while looking perfectly healthy from every other screen.
See who is on the roll — as a count, which is what the question needs. No child is named on this screen.
Close a classroom — once, deliberately, with the roll read first and the classroom's own id typed back. Nothing is deleted: what those children were taught stays on the record.
Who may teach, and where is the room next door, and the Author console is where the lessons themselves are written.