What kind of mouse do you have?
Try to find an exact match in the first box at right. If you can't find an exact match, you can choose one which is compatible with yours. Otherwise, choose Generic.
Do you have a PS/2, Bus or serial mouse? (Hint: If the connector on your mouse is round, you have a PS/2 or a Bus mouse; if it's rectangular, it's a serial mouse.)
If you have a serial mouse, you'll need to pick the device and port it is connected to.
The X Window System is designed to make full use of a three button mouse. If you have a two button mouse, Red Hat Linux can emulate the middle mouse button.
If you have a two button mouse, select the Emulate 3 buttons option. Once configured, you can click both mouse buttons at the same time to act as the middle mouse button.