When installing from the setup installer a shortcut for starting DbVisualizer should be created on the desktop.

The problem is that some desktop environments used in Linux and Unix - like GNOME - do not support icons on the desktop by default. This has been seen on Fedora 31 for instance.

The result is that the shortcut created during installation will not work and maybe not even be visible. 

The solution is that you install and enable certain add-on programs. More details on this can be found by searching on the internet.