[R] program and comment

[Guojun Zhu]

Hi.  I am a newbie to R. I need to do a courses
projects with some manipulation lots of data record
and some back-and-forth linear regression.  I do not
want to spend $100 for a SAS lincence, which professor
used.  So I decide to start to learn R to finish it. 
I am using R in Windows.  I feel it is somehow works
like mathemica.  I try to write the work into a little
program for future reference. (My data soon exceeds
the workplace.) So that should be a script, right? 
Then I can load it in "file/source R code".  One thing
puzzles me is that how to write  comments in the
script.  I googled internet and the archive and did
not find any clues.  

First, can anyone confirm that I took the correct
approach for the problem?  I understand R is quite
different from program language like C/Pascal which I
am familiar with and seems people write it with quite
different style.  Second, can anyone show me some idea
about how to write  the comment.  Thanks.