Course rules are used to enforce how the student navigate through the lectures and download course completion certificates.
To setup, click on the course options icon and select "Add Rules".
In the 'Rules' page, you have options to setup traversal, course and test completion rules.
Check this KB note to understand how to create and deliver course completion certificate.
You can setup completion rule individually to each lecture. To do that, go to 'Course materials' view under course options.
Click on the 'wrench' icon in the lecture bar to open the lecture completion rule popup.
The default option is "Mark as learned" checkbox. Students mark each lecture as completed to move on to the next lecture.
You can enable the following option to force students to pass all the tests or a specific test to mark the lecture as completed.
Finally, you can setup time limit to force the student to spend specific time period on this lecture page. Lecture will be marked as completed after this time period in seconds.