1) Use the File menu to select "Print"
2) This should bring up a window which allows you to choose your Printer, define the paper range, number of copies etc. Next to the printer name is a Properties button (there is an option button at the bottom of the window - ignore this).
3) Click the properties button. This will bring up a window in which you can set the paper size, orientation etc. Each printer properties will be unique to the printer, but will have the same type categories displayed as Tabs along the top of the window (i.e. my HP has Paper, Graphics, Device Options, and Postscript).
4) On one of the Tabs you should find a Postscript Option. Select this. You should now be able to set "Postscript output format". Normally this says "Postscript (optimize for speed)", but you can select an "Archive format".