Click on the word Navigation to see the settings for the Course Navigation pane.
The Settings navigation link is where you can modify the navigation of your course. Depending on your permissions, you can edit differing levels of the course settings.
In the Navigation tab, you can modify the Content Navigation links listed in your course. You can drag and drop to reorder and hide course navigation links. Just click on the item you want to move and drag it to the position you want.
To hide items from your students, click on the menu item (ie. Announcements or Assignments) and drag them to the area where it says to "Drag items her to hide them from students"
From the Canvas Instructor Guides