Alright, getting somewhere now.
I have the Oracle Management Server up and running, can connect using Oracle EM.
However, when I try to click on my database, I get a login screen. I have used the NT Administration Assistant to grant my NT account, which has Local Admin on the NT Server upon which Oracle is installed, OS DB Admin and OS DB Operator membership, at the server and Oracle DB level. Also made myself External OS user, and granted myself Local Roles in my DB.
So, what do I enter in the DB login screen in Oracle EM?