As an instructor you have the ability to turn your course on (make visible) or off at any time to your students. To turn your course on/off, or make it visible/invisible, to students:
Step 1: From the Administration menu block, click on Edit settings.
Step 2: Under General settings use the Course visibility drop down menu to select to Show or Hide your course.
Step 3: When finished, click the Save changes button at the bottom.