Removing staff or students from your course works exactly the same.
You can remove staff and students who have been manually enrolled or self-enrolled.
You cannot remove students who have been enrolled by "external database" (PeopleSoft).
Staff or students enrolled by "course meta link" must be unenrolled from the source course to be unenrolled from yours.
Staff (or sometimes students) who are enrolled by "category enrolment" cannot be removed by you, as they have been assigned to their role at the category level to all courses in that category. If you feel that there are staff there by mistake, please contact your programme administrator or firstname.lastname@example.org to clarify.
Instructions for removing manually or self-enrolled students:
Instructions for removing meta course enrolled users
» Guide to Moodle