Here's the skinny, search the board if you need more in depth info
Where /dev/hdx is the device as reported by your Hardware Browser
create the partitions, then:
mke2fs -j /dev/hdxx
Where /dev/hdxx is the partition(s) you have created, this will create a blank ext3 filesystem, which can then be mounted:
mount -t ext3 /dev/hdxx /mnt/wherever
Where /mnt/wherever is where you'd like it mounted.