When the program has been started, it prompts for O files (binary or formatted). Any number of each can be read in. If you are starting for the first time you MUST define startup.o, menu.o. You should also define the name of the file defining the connectivity to be used when creating molecular objects, all.dat. The program always asks if you wish to use the display or not. Some commands do not need the display so answer according to what you want to do. If you say that you don't want to use the display, and then activate a command to access the graphics system anyway, no graphics window will appear. When starting for the first time, the program will prompt for any files that it needs but are not defined. If unsure, strike the return key to accept the default. It will also issue a warning if the user's database was created with a different version of O.