Macs before about 2006 such as yours use the PowerPC architecture rather than the i386/AMD architecture , and you'll need a distribution that supports 32-bit PowerPCs. Debian is probably your best option, as it is outrageously stable and well documented. You can download entire CDS and DVDs of its software if you don't have an Internet connection. From when I tried on a slightly older Mac a few years ago, it can recognize a Mac and installs the right boot loader.
For selecting a DE if you wish, you'll probs want to use a very basic windows manager at best if you have <128 MB RAM, between 256 and maybe 768 MB you can do XFCE, LXDE, or MATE, and if you have a ton for a PC of that era, maybe GNOME or KDE.
Links to download Debian:
https://www.debian.org/distrib/netinst
Select a POWERPC or PPC image or else nothing will happen. To boot from a CD, press C while the computer boots before you see the OS X boot screen.
I did this a few years ago on a 1997ish PowerBook G3 and plan on doing it again soon. I'll be glad to help when I have time.
