See students, staff, and parents institution-wide, and invite Principals to run each school.
Students, Staff, and Parents each give you a combined view across every school in your institution — filter by school when you need to narrow in.
Day-to-day additions (enrolling a student, hiring a teacher) are usually done by each school's Principal from their own dashboard.
Go to Administrators → Invite Principal, pick which school they'll run, and send the invite.
They receive login credentials scoped to that school and get their own Admin dashboard.