If you are tying to install the tar.gz file for the KDE client from this source:
http://sourceforge.net/project/showf...kage_id=117437
The steps are
1. open up a terminal
2. use the change directory command to get to wherever the .tar.gz file is
cd /directory/subdirectory
3. become root using the su or sudo command
4. unzip the .tar.gz file using the gunzip command
gunzip file.tar.gz
this will leave a .tar file
5. uncompress the .tar file using the tar command
tar -xvf file.tar
This should uncompress all of the files in the .tar file and put them in a new directory where you are located.
6. Enter the new subdirectory using the cd command
cd new_subdirectory
7. Read the INSTALL file that normally comes with such software using your favorite editor
gedit INSTALL
8. Normally the install process for source code is
./configure
make
make install
If you are able to use the ubuntu commands (apt-get and such), it might be easier, because that way you will be able to update the software more easily.
http://openkiosk.wiki.sourceforge.net/installation