As a parent you can view the lessons and assignments that teachers post. Locate and click on the course that you are interested in. The list is by school level (elementary, middle, and high school), by grade, and then by subject.
When you click on a course you will be asked to login. Click on the button that says "Login as a guest". You will not be able to post anything or participate in the class but you may view assignments, class work, and homework sets.