graphics guide?

I am trying to create some graphs with R and it seems to be able to do
what I need. However, I have so far not been able to find any sort of
explanation of how the graphics system works. I am for instance trying
to create a multiple figure, and I seem to have to call plot.new()
before every new plot command, I have however not found any
explanation of what this actually does. ?plot.new does give an
explanation, but it is explained in R, so to speak. Where do I find
out what for instance a graphics frame is?

Thanks,

Karin
-- 
Karin Lagesen, PhD student
karin.lagesen at medisin.uio.no
http://www.cmbn.no/rognes/