You may have just 'temporarily' downloaded it to only view inside the browser. While viewing it move the arrow down and over to the right and you may see a few icons pop up. A zoom in and out button (magnifying glass). Also one would look like an old floppy disk. This is to 'save/download' the .pdf. And one that looks like a printer to print obviously.
If that doesn't work maybe providing more info would help. Such as are you on Windows or Mac? Kind of device (laptop, tablet, phone, etc). Web browser being used to download the file (Firefox, Google Chrome, IE, Safari).