Booking page
One tab per teacher, free times as buttons, and the confirm dialog.
A tab for each of your child's teachers. Free times are buttons; greyed ones clash with a meeting you already have. Existing bookings with that teacher are shown at the top of the tab. Pick a time, choose the child, tick anyone else attending, Confirm.
See Booking, changing and cancelling.
When you confirm you can also say what you would like to discuss (the teacher sees it) and, on a "parents choose" conference, pick By video or In person. If a teacher is fully booked, the tab offers Join the waitlist — see the waitlist. To book every teacher at once, use Schedule.