First decide where you want to install iQgen. We assume that you choose /usr/local, but you can use anything you like - just make sure that you remember to replace your installation root directory wherever we refer to it throughout the documentation. Change to the directory you just created and extract the archive's contents using the following command:
gzip -d -c iQgen-x.x.tar.gz | tar xvf
This will create a directory called iQgen under the current directory. In the bin subdirectory of the installation root, you will find a script called iqgen.sh. Edit this file and set JAVA_HOME to the appropriate value, e.g. /usr/local/jdk1.3.1