Put the Panther Install CD #1 into the cd rom drive and
click on the Install Mac OS X icon when it shows up on
the desktop or reboot the computer while holding down
the C key as it starts up.
Select your language and press continue - then accept the license agreement, choose the destination volume, and click on Options.
Select the Erase and Install option and choose Mac OS X Extended (journaled) in the Format disk as window and click OK.
Now click Install (the Customize option is for advanced users)