Email setup for beginners?

Hi

I'm pretty new to the whole Linux thing, so bear with me.

I got my Linode yesterday and figured out how to setup the LAMP thing pretty easily. So I was pretty excited about the whole thing. I could make websites, yay! :)

But now I am completely stuck on trying to set up email. I followed the instructions here: http://library.linode.com/email-guides/ and, knowing nothing, just started with the Citadel-tutorial. "It has to be first on the list for a reason" I thought. :)

That went pretty well, I have the Citadel web-interface up an running. But now what? I can't make heads or tails of the thing. :)

There are "rooms" and "floors" in there. What the..? I just want to set up email addresses for my domains!

Do I move on to step 2: Postfix guides?

I can't really figure out wether Postfix is something I ALSO need to install or just another way of doing the same as I've already done by installing Citadel… And frankly - the mile-long instruction in the Postfix guides page scares me a bit. :)

Especially since I've already installed MYSQL during the LAMP tutorial, so I don't really know how to start the Postfix tutorial.

So, to cut to the chase: I just want to set up emails for my domains. Where do I go from here?