This screenshot displays the Microsoft Management Console. 
It is divided into two panes similar to Windows Explorer.

The left pane displays the following hierarchy of objects:
Oracle Administration Assistant for Windows NT
Oracle Managed Objects
The actual computer hostname
The actual database instance (ORCL, for example)

In the left pane, right-click the database instance (ORCL, for example).

In the pop-up menu that displays, choose Connect Database.