Most modern PC towers or base units have more than one graphics output, eg HDMI and SVGA or display port or DVI. Laptops less so, and you may need a dock if on a laptop.
If you have more than one base unit display port, then hook up two screens and then tweak your display settings in control panel to select how your screens are represented.
Let us know which hardware u have, if this doesn't make sense.
Cheers