Novice Exim user wants to set up a mailing list

[Landon]

Greetings! I hope you can help me.

I've got this up to date debian server sitting on the Internet and I
want to be able to send mail from it.
I have the default Exim package installed.
The mail to/from my domain is currently routed through google mail servers.
I want to keep using google as my mail handler while also being able
to send mail from my domain name from my server.
I also do not want to receive external mail addressed to local users
on my server such as "root" etc.
I only want to receive the necessary external mail messages that are
required to make the mail system function.
After I set up my mail server, I will set up mail software that will
allow me to manage a small mailing list.
The Exim server should accept subscribe and unsubscribe requests
messages from people who use the mailing list.
I would have set this up a long time ago, but I really have no idea
what I'm doing or how to do it. I know very little about how Exim
works.
I am hesitating on setting it up because I am afraid that I will miss
configure Exim and allow spammers to use it to send spam.

So... How difficult is it to set this up for someone who knows
virtually nothing about Exim?
Is there an up to date guide somewhere on how to configure Exim to do this?
I don't mind reading about how to set this up, but I also don't want
to have to read a 500 page book to figure it out.

Landon