You might start at
http://www.mvps.org/dmcritchie/excel/excel.htm#tutorials
Those references should certainly get you started many are designed
for starting university students without regard to their major so they have
to cover a broad range of students some with and some without computers
(though I guess there won't be many without some computer experience).
The more specific you can ask a question the more likely someone can
come up with something specifically oriented to your requirements. I think
of the tutorials as a starting point so you never have to start with the
Excel for Dummies book and can purchase a more useful book later that
you can use as a reference. Purchasing a book later is not really necessary
it would be just a lot faster than spending all your free time in the newsgroups.
