This is a big time confusion, we encountered with users that they are not able to find out which widgets they should add in Instructor or Vibebp Sidebar
Instructor and vibebp Member Sidebars are for instructors and administrator user role resp. The instructor Sidebar Widgets will be visible for instructors and Student Sidebar Widgets will be visible to Student user Role.
Instructor Sidebar - Add instructor related dashboard widgets which will be visible to instructor user role
Vibebp Member Sidebar - Add instructor related dashboard widgets which will be visible to Administrator User Role
Student Sidebar - Add student related dashboard widgets which will be visible to student user roles
In these Sidebars you can only add "Dashboard Widgets". As you can see the description is already added in Appearance > Widgets that which widget is for which user role. So please choose according to that