Best or Default install location for KDE?

[Brett Brewer]

I installed YDL 2.3 using the standerd web server preconfigured packages.
Woked like a charm. Now I'm looking to add some GUI tools such as KDE. Where
should I install this? Will the RPMs automatically install files in specific
places or is that entirely dependent on where I saved the RPM files? Also, I
downloaded all the latest KDE rpms to a directory
(/home/username/downloads/rpms/kde) before I managed to figure out how to
mount my CD-ROM with the KDE rpms included. Should I use the latest
downloads that I found, or should I install from the CD for compatability?
Mostly I just have no clue where to install things. In my root direcotry (/)
I have the following other directories (some from previous aborted linux
installs):

bin
boot
dev
etc
gdm
home
initrd
lib
lost+found
mnt
opt
proc
root
samba
sbin
tmp
usr
var

I have no clue where to install various packages or whether they know where
to install themselves and I just need to keep track of the source RPMs.
Please help.