After initial installation, you need to use http://127.0.0.1:2002 from the device CSACS is installed on.
After that, I think you are "prompted" to setup a local username and password for administration.
1. Select Administration Control from the left menu bar.
2. Select Add Administrator.
3. Enter an Admin name and password.
4. Select the Grant All option.
5. Select Submit.
If you wish to force ACS to authenticate administrators logging in on the ACS host itself, perform the following additional steps:
6. Select Session Policy.
7. Deselect Allow automatic local login.
8. Select Submit.
Click the "X" in the top right-hand corner of the screen. Then try to login. You should be presented with username and password fields.
Use the credentials configured above.