You will use Enterprise Services Manager to test the connection to the server.  To access the Enterprise Services Manager, go to the start menu then All Programs CarpeDatum Enterprise Services ES3 (or customized Default Web Site).
 

Depending upon your configuration, you may see a login prompt, similar to the following:
 

ES Manager_Startup Screen

 

If you receive an error message, check your configuration settings and re-try the connection test.  Input your IBM® Cognos® TM1® credentials and click on the Login button to start Enterprises Services.