AppGate is available as a virtualised appliance. You can download the most recent release from here
and you should contact firstname.lastname@example.org for the required username and password. There is more information in the manual about installing appliances including detailed installation guides.
After installation - the configuration will be done through the web-based AppGate console. Full details of how to do this can be found in the configuring the first appliance section of the manual.
NOTE: For Trial or production use please contact email@example.com.