A Moodle course and authorization will be automatically created. As soon as courses are allocated, students will have access to the corresponding Moodle course. If you would rather not have this, you can hide it from students during the time you are still working on the course syllabus, etc. In the Moodle course, go to "Administration" > "Course Administration" > "Edit settings". Under "General" > "Course visibility" change "Show" to "Hide". Do not forget to change the setting back once you have finished drafting the course.