The Sensei Course Progress widget is a free plugin which you can download from here.
The Sensei Course Progress extension is a simple widget you can add to your sidebar to display your learners’ current progress within a course.
To add the widget to your site, go to Appearance > Widgets, and drag the Sensei – Course Progress widget from the left, to any of your widget areas on the right. (The widget works best in a sidebar, so it displays alongside your lesson content).
The widget will only display on lesson and quiz pages, and will show learners all the lessons in the current course. It will also indicate which lesson they are currently viewing, and which lessons they have already completed: