Sidebar in Library view - landscape mode

The sidebar in the "Library" view in iTunes U for iOS shows Posts & Assignments but I cant figure out how to have it show the posts & assignments from the course that I am currently working on; it seems to have selected a course to show these items for and there doesn't seem to be a way to change what shows up in the sidebar.

Anyone know how to change which course the sidebar pertains to?

Is there a User Guide for the iTunes U app?