New to rt, sendmail

Hi,

I seem to be having a lot of trouble setting up the email configuration.
I actually don’t really seem to know what’s going on… Does the server
which rt is set up on have to be a webserver w/ a domain name? I looked
into some webservers and it seemed that they wouldn’t let me install rt
on it. I set up rt on a local server, and was able to get apache to
work. When I started a new ticket i received an email to myself from
"The default queue via RT support@example.org." How do I send email
back to rt? Where do I change example.org?

Thanks,
Allen