Users navigate through course pages via course tabs:
The Course Tests tab has all the tests from the course displayed on one page.
The news tab shows the page with posts from your course author. You can also leave comments on each post.
The Student groups tab has the list of available student groups of this course.
You can navigate through course lessons via the Lessons menu:
If the lesson has more than one part, there will be a small “+” sign near the lesson title: