We suggest opening your PDF files in Adobe Reader for the best experience. You can download Adobe Reader for free here: https://get.adobe.com/reader/
If you are operating on a Mac, the files may automatically open in 'preview', rather than Adobe Reader. Open in Adobe Reader by right-clicking on the file in your Finder and choosing Open With > Adobe Reader.
If you are opening the file in Adobe Reader and still finding blurry or formatting issues on pages please make sure you have the lasest version of Adobe Reader. Do this by opening Adobe Reader, clicking on the 'help' menu and choosing 'check for updates'.