Saving and opening files is just like any other Macintosh program, so I won't go over it again here.
Printing, though, is slightly different: you can print normally or you can print at high resolution. High resolution printing is always recommended.
When you choose "Print High Resolution..." from the File menu, your plot will be prirnted at the highest resolution the currently chosen printer will support, up to 600 dots per inch.
You can still print "normally" of course (choose "Print..." from the File menu), but it looks really chunky, and is only included for people who can't print at high resolution, for whatever reason.