When you download the file, save the file to a drive, name the file. After you have saved the file, reopen the file from your drive. It should be opened to Adobe Acrobat Reader and when you print from Acrobat Reader, the print window will allow the option to print by PDF size. You can also change the paper size you use to manually manipulate the paper sizes when in the print command from Adobe Acrobat reader.
Remember, after you have saved the file to a drive, you must close it, then reopen the file and it will open in Adobe.
If you don't have Adobe Acrobat Reader, you can download for free from the web.
Hope this helps.