There is no required order to the switches. The file name can appear anywhere on the command line; SAOimage assumes that any token that is not part of a recognizable switch is the file name.
Many switches have two names, one literal and one abbreviated. In such cases the names are completely interchangeable. The longer names might be used in a script where a later reader might wonder what the switches do. The abbreviated names save typing on the command line.
Once SAOimage is running, you may enter a new command line, changing some of the settings and/or reading in a new image from disk. A few switches, such as the display server, cannot be changed from their initial settings.