Once the server starts, it is marked in the configuration database that it should be running. If it stops, or if you reboot the machine, the administrative server will automatically restart it. Even if the administrative server fails, it will continue to run.
Then, open a Web browser on a client computer in your network and go to http://hostname_or_IPaddress/servlet/snoop, which is a standard sample servlet installed by default. You should see information on /servlet/snoop.