Faculty managers have permissions which mimic those of the heads of schools/departments, but duplicated for all departments/schools in their faculty.
To change managers for a faculty, navigate to the superuser dashboard, then use the drop-down menu (a) to select the faculty to edit. Use the search field (b) to filter people using first name, last name, and username. Use the checkboxes (c) to select the person to add to the current faculty, and click the Save (d) button. Existing managers (if any) are listed on the right hand side (e).