Inputting Japanese

I've been trying to figure out how to input Japanese kana/kanji into word processors and etc under Fedora Core 4. Most of the sites I've run into say something like... "download this tarball and then install all these things and then type this big huge complicated thing into a terminal before you use the word processor". Every time I've tried this, none of the stuff they want me to download actually makes. To compound this, my father keeps insisting I do updates and download the latest whatever from Red Hat, the result of which is that I now have 3 different kernals on my computer because only one of the earlier ones can actually succesfully connect to the internet via wireless. The update apparently also made it so that none of my fonts work either, which might be a problem if that darn thing ever gets installed.

So... can someone explain some way to input Japanese in some sort of simple English and where to get these programs, and how to tell if I've already got them, and how to make them work?

And if someone could speculate as to why my fonts are all caput, that would be nice too.