It doesn't work quite like that
You make a postscript file by printing to file using a driver for a postscript printer. you will need to choose one and install the driver to your PC. You then print in the usual way. You don't, of course, need to have the printer actually attached to your machine.
Best thing to do is choose a commercial printer, find out what printer or imagesetter they use and use the same driver - its more reliable/predictable that way.
There are others who use the Forum (e.g. Mike K) who know more about this than me and hopefully a post or two will follow....
Regards
John