Let's see...




In the picture, Computer1 is the main/localhost, Computer2 is bottom left, Computer3 is top left, Computer4 is top right, Computer5 is bottom right.

And the mouse moves seamlessly to all of them. The mouse/keyboard is of course connected to Computer1.

EDIT:
You mentioned that your knowledge of networking is limited, mmmkay, now lets see... assuming that all of your computers ARE networked together under the SAME network... all you need to know is the name of the computer. (usually done after installing windows) But you can find out the name by going into Control Panel>System>Computer Name>Full computer name: xxxxxxxxxxxxxx

My computers are named Computer1, Computer2, Computer3, Computer4, and Computer5 to better understand the setup.

Sorry if it didn't make any sense, and if it did... then cool.