There are three ways by which you can connect 3 additional monitors with your computer :-
1st : – If your computer’s video card supports two or more monitors then it can easily be done with windows. All you need to do is to connect the screen with your computer and let the windows do the work.
2nd : – You can put additional video cards on your computer’s mother board, a standard motherboard allows you to install 3 video cards.
3rd : – You can use an additional hardware (VGA splitter), you can connect 3 or more monitors with your computer depending on the splitter you use.