A help is provided at every level. If you enter help (or simply h) at the promp bda>, it will open a new window and you get the prompt help> [dbms], dbms being the default value. It displays information about the program, and suggests to continue reading the text on bda, which in turn proposes yo to continue with agent, to discover the allowed agents.
If you for example chose meas, your prompt is now measure>. Typing help will display a list of the datatypes for which you can get data. After you selected a datatype, let us say mk, the prompt becomes measure mk>. Entering help again will inform you that the program is waiting for one or several star numbers. This help facility will guide you at every prompt during your database query session.
It may be useful to keep the help window that is opened when you enter help at the prompt bda> to look at the list of agents and get information on them. You can also close it and you'll get an icone with the label "BDA help". When you say bye to the prompt help>, the window will close.