Viewing the PDF documents requires the Adobe Reader or another program that will read PDF files. If you do not have it, you can get it by clicking on the Adobe logo.
To view the document in your browser (using the Adobe Acrobat Reader plug-in), simply click on the link and it will open in a new window (or tab). To save the file, right-click and select "Save link as" or "Save target as" (depending on your browser), and select a location to save the file to.