Windows: right-click on the link/icon and choose "Save As".
Mac: Ctrl and click on the link/icon.
Adobe Acrobat Reader is a free software that lets you view and print Adobe Portable Document Format (PDF) files. It could be already installed on your computer (once the file is downloaded, try to double-click on the file's icon), otherwise you can install it yourself. To get Acrobat Reader, click on the icon, and follow the instructions.