SSO
Java EE Policy Agent Setup
The instructions have some details missing.
Click Access Control.
You will see the default Top Level Realm. You can read more from Oracle on what a realm means.
References
http://openam.forgerock.org/doc/agent-install-guide/OpenAM-Agent-Install-Guide.html
https://wikis.forgerock.org/confluence/display/openam/Add+Authentication+to+a+Website+using+OpenAM