Some teachers will be adding readings and other course materials through the website. They have a possibility to notify you about these information and also they should inform you in class whether they are going to use this feature. However, it may be useful if you check the website to see if there is anything new for your courses.
From now, you will find a new section on your account ("Course Resources") - follow the link to the appropriate semester to see a list of your courses and related course materials (if any).