Am I doing something wrong?

[duksrule]

I have a site that is hosted by WESTHOST and have installed RoundCube Webmail 0.1.rc1.  It let me set up accounts for mail, will let me log onto those accounts and even compose an E-mail.  Problem is that it won't send the mail and if I send an E-mail to those accounts from another account it is returned.

I don't see anyplace to check or change settings.  Anyone able to point me in the right direction to get this program running?

[JohnDoh]

Check the SMTP settings in [RCroot]/config/main.inc.php. also consider upgrading to 0.2stable, 0.1rc1 is very old and no longer supported.

[duksrule]

How can I do those two things?  I am a newbie and am at a total loss