To Use One Monitor for Two Computers, you have to buy a kvm switch and cables (if needed). After that, Connect your monitor, keyboard and mouse to the kvm switch. You need to take the monitor cable that you would ordinarily plug into your computer's video card. You must connect it to the kvm switch. You should plug your keyboard and mouse into the kvm switch as well. Then, connect each computer to the switch. Using the built in cables or those you purchased, you can connect from the kvm switch to the female connector for your video, keyboard as well as mouse on each computer.
Next, Plug in your monitor and power up both computers. Upon boot up, you must see the display of the computer that is switched on. To switch to the second computer, you have to flip the physical switch on the kvm. You need to use this switch to trade back and forth between computer one to computer two whenever needed. If your kvm supports more than two monitors, you must switch to other computers by using a keyboard shortcut or an on-screen display menu.