This calendar is updated often so that you can see what is going on in the class. To find your Weekly Web Notes, go to the week that you are in and click the Weekly Web Notes colored bar (event). Then be sure to click "More Details", and from there you should be able to fully download the file you are interested in. The same two step process applies to Files and Announcements for the week.
And below you can find the file with instructions for setting up your Online Homework account: