To launch FDR on Mac OS X simply open the FDR application that you have
downloaded (normally this will be inside Downloads in your home folder). To
launch FDR under Linux simply type fdr4 from a command prompt (providing the
installation instructions have been followed). Alternatively, a particular file
can be loaded by typing fdr4 file.csp into a command prompt.
However FDR is launched, the main window that is presented is known as the session window, and is documented further in Session Window.