Restrict course access
By default when a course is created and set to the owned by the organisation, unless the courses menu item is hidden for your students (click here for more information this), they will be able to view the contents of courses and all teachers in the organisation will have access to the course and associated modules. See controlling access for more on this.
However, you may want to limit/restrict access to specific courses for teachers and/or students in your organisation.
To do this, select the course and then go the the Course Permissions tab
By default, the courses are unrestricted but to change this to only allow specific teachers to access the course, select the bottom box and a list of all teachers in the organisation will be shown.
Simply select those teachers who you wish to be able to access the course and the associated modules and units.
Students will not be able to access/view the contents in this course even if courses menu item is not hidden