[Exim] help about smtp

Hello dear friend.
I have linux redhat 7.3 , and I have installed exim ver3.3, now i don't
know how I should set smtp on exim, and switch it on sendmail.
Thanks by regards

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 Soheila Khademi
                                           e-mail: khademy@???
                                                  soheila@???
 Network Admin                                    khademi@???
 Network Services
 Center For Information Services  (CIS)    http://www.iut.ac.ir
 Isfahan University of Technology (IUT)    Tel: 98 31 3915840-1
 Isfahan, IRAN                             Fax: 98 31 3915805
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