Administering with MySQL DB

Hi list, Im completely new to freeradius, I have installed the server with MySQL and also got the dialup web GUI up and running. However its still not clear to me how I add new NAS devices, you dont appear to be able to do that in the GUI. I just want to add a system by IP address with a secret. Do I need to manually do an insert into mysql? If so can someone give me a pointer to how the data should be entered? Or any other help!! thanks! Andy.