Most of the items that can be added to a Lessons page can be made "required." That is, students must open (if the item is a resource) or complete (if the item is a forum posting, quiz, assignment, question, comment or student page). Further, the Lessons tool allows instructors to require students to complete one item in the list before allowing access to other items in the list.
Click on the Lessons tool in the Tool Menu to display the page.
Note: The default or blank Lessons page contains text and images that explain the basic functionality of the Lessons tool.
Check Don't Release Item Until All Prerequisites are Completed option, then click Update Item.