Based on your preference, set KDE_PREFIX.

If KDE is your desktop of choice:

export KDE_PREFIX=/usr

If you want to try-out KDE:

export KDE_PREFIX=/opt/kde-3.4.1

Remember to execute ldconfig after installation of libraries to update the library cache.

If you are not installing KDE in /usr, you will need to make some configuration changes:

You should consider installing the desktop-file-utils-0.10 package. Though not required, this package will allow you to easily use existing .desktop files in /usr/share/applications (and any other locations identified by XDG_DATA_DIRS), and automatically add these applications to the KDE menu system.

Add to your system or personal profile:

export PATH=$PATH:/opt/kde-3.4.1/bin
export PKG_CONFIG_PATH=$PKG_CONFIG_PATH:/opt/kde-3.4.1/lib/pkgconfig

Add to your /etc/ld.so.conf:

cat >> /etc/ld.so.conf << "EOF"
# Begin kde addition to /etc/ld.so.conf

/opt/kde-3.4.1/lib

# End kde addition
EOF

Add to your /etc/man.conf:

cat >> /etc/man.conf << "EOF"
# Begin kde addition to man.conf

MANPATH /opt/kde-3.4.1/man

# End kde addition to man.conf
EOF