You need to initialize it so that there is a file system on the drive that enables you to store family videos, music, etc. on it.
In Disk Utility, choose Erase. Then choose Mac OS Extended (Journaled). This is HFS+ Journaled, AKA, Panther's default. It is readable by OS 8.6 and up.
History lesson!
MFS was Macintosh File System, used by System 1.0 and 1.1. Used also in 2.0
HFS replaced MFS. Stood for Hierarchical File System. This meant that folders were natively supported instead of just being remembered where everything went. HFS lasted through System 7
HFS+ was just an upgrade to HFS, so that it would remain viable for larger hard drives.
Journaling is something new in Panther that allows you to recover better after a crash. I've never had to try it out, so I can't really help you there, but I do know that it works backwards with any other HFS+ file system.
Right, so now you know your file systems.
Jumpers tell the drive and the computer where it is on the cable. Used only on Parallel ATA cables, NOT SATA (Serial ATA) which your G5 uses. SATA has one drive per bus. Simple. PATA had two, so you needed a jumper telling the drive if it was the master or the slave on the bus (1st or 2nd).
Just use Disk Utility, Erase the new drive, and voíla! New drive!