What kind of mouse do you have?
Do you have a PS/2, Bus or serial mouse? (Hint: If the connector your mouse plugs into is round, you have a PS/2 or a Bus mouse; if it's rectangular, it's a serial mouse.)
Try to find an exact match in the first box at right. If an exact match cannot be found, choose one which is compatible with yours. Otherwise, choose the appropriate Generic mouse type.
If you have a serial mouse, pick the device and port it is connected to in the next box.
The X Window System is designed to make 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. After the installation, you can click both mouse buttons at the same time to act as the middle mouse button.