download the installer for your operating system the download page.
On Ubuntu Graphviz can be installed via:
apt-get install graphviz libgraphviz-dev pkg-config
install the program in a directory like
%SCRIBESTOOLS%\Graphviz\into the PATH environment variable.
To test your installation type the following command in a new shell. It should display the version of graphviz.
You can try the
gvedit, a very simple graphical interface. It is not really
useful though as Graphviz is mostly used by other programs.