I haven't figured out how to go back to the previous screen in a lesson, or how to move forward if I haven't completed the exercise correctly. I feel boxed in. What can I do?
In the old courses, just use the menu at left (click the lesson name at bottom). The menu will permit you to access any lessons in the module.
In the new course, we cannot go ahead of an incompleted lesson, but we can go back. Use the menu at left.