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.
Go to Lessons.
If you titled your page something other than Lessons, select the title of the page as it appears in your Tool Menu.
Click Edit for item that will be required.
Check Require that the student submit this assessment, then click Update Item.
Note: For graded items, such as assignments or quizzes, you may optionally specify a particular point value that must be earned on that item before the requirement is met.
Notice the asterisk.
Notice that Required items are indicated with an asterisk to the left of the item.
To conditionally release based on prerequisites:
Click Edit for the item to be restricted.
Specify completion of prerequisites.
Check Don't Release Item Until All Prerequisites are Completed option, then click Update Item.
Notice prerequisite text.
Notice that items that are conditionally released display [Has prerequisites] next to the item.
In the example shown above, Assignment 2 cannot be opened until the required Assignment 1 has been submitted.