YDL4 on external firewire hard drives..

[Chun H. Fong]

Hello,

I have an iBook G4 ( 1Ghz - early 2004 model ) with 
a Lacie External FireWire400/USB2 160GB Hard Drive.
It's running Mac OS X 10.3.8 ( latest version ) on 
the internal iBook HD.

The external HDD was partitioned into 4 separate Volumes (partitions )
using the Apple OS X  Disk Utility. 
 First  Volume- OS X Volume clone backup ( using intego backup ) 
 Second Volume- working data , temporary space , ( like /tmp )
 Third  Volume- Space for YDL to be installed ***
 Fourth Volume- Space for NetBSD or OpenBSD ( I haven't decided yet )

I would like to install YDL4 on the external Hard Drive third partition
and NOT on the iBook's internal HD. I'm not familar with OpenFirmware.
How do I do this ?? What are the steps for complete 
mac and linux newbie?? 

Thanks,
CHF