When you click on the file in the course and it opens. You will see at the top, "If this item does not open automatically you can open Lecture 01 here"
Click on the "open Lecture 01 here". This opens the pdf in a new browser window. You still might not be able to see all of the document. If so, in the upper-right corner of the document, it gives an option to "Open in Acrobat". Click on Open in Acrobat and you should then able to see the entire document.