confused about mailman and postfix setup

Hi all,
I’m new to Virtualmin. I’m trying to set up a mailman list on a sub-server such as lists.example.com.
I have a sub-server created and mailman is enabled on that server. I have a list created.
When I try to send email to the list name, I get an email back saying that the mail loops back to itself.
I’m not sure what virtualmin sets up in postfix and mailman automatically and what I need to set up myself.
I can’t find any documentation on this. Can anyone give me a rundown of what I need to do to get mailman working on a sub-server?
My dns is set up and working correctly. I’m sure this is just a config issue in either postfix or mailman.
Virtualmin was installed using it’s install script on a brand new Ubuntu 16.04 vps.
Any help would be apreciated.

Shouldn’t Postfix’s alias database get automatically updated? However, it’s being said on https://cheapessaywriter.net that when a list is removed/added, the aliases.db file will be updated, though it won’t automatically run postfix reload.