Just pick the one from the list that matches your hardware. If you have any mouse connected to a PS/2 style port, select the PS/2 Mouse option. If you have a 2 button mouse and want to emulate the third (middle) button with a simultaneous click of the left and right buttons select the ``Emulate 3 Buttons?'' checkbox at the bottom of the screen. If you have a serial mouse, you will next select which serial (COM) port to use.