Ok, we're getting some info that hopefully leads to solution for you ...
This part ... "bridge mode so its on the same IP range" sounds like the Virtual hosting is VirtualBox and you have a Ubuntu 'guest' OS 18.0.4.
Is that correct?
Also your 'panel' is Webmin ... which is perl based and has a built in web service of it's own which by default runs on port 10000 ... can you access the Webmin from another workstation on your network?
IF so, the URL to your webmin would look like http(s)://192.168.0 or 1.some number:10000/
So if I am understaning your setup ...
A machine - running VirtualBox - guest OS Ubuntu 18.04 - and in that guest OS a webmin running on port 10000 - and you want to run Apache/MySQL in the Ubuntu 18.04 so you can run a Moodle.
Now some network/technical questions ...
In VirtualBox config one cannot set a static IP address for virtual guest OS's. So using Webmin, you've been able to set virtual eth 0 (a nic) to a static IP address in the range of your private 192.168.0 or .1 range. It's NOT DHCP is it?
Through webmin you have started MySQL service and it has a root user with password. Have you created a database for moodle? Character set utf8mb4 with collation of utf8mb4_general_ci?
Through webmin you have started Apache and a 'phpinfo' page works from /var/www/html/ directory. Shows all the required PHP extentions for running Moodle are installed.
One can Google and find many many how2's ... but I've not found one specifically for your combo ... IF I am correct about your set up.
I searched Google using:
"installing Virtualbox Ubuntu 18.04 Webmin Moodle"
and got hits but nothing as simple as a 1,2,3,4 - for all of it.
So one would have to find separate tutorials for the parts keeping in mind what's required for Moodle to run.
BTW ... I do run VB on this Mac ... it does have a Ubuntu and a CentOS guest OS that I can run and each of those have webmin and a Moodle on them.
No ... I don't have a tutorial ... I use blogs on net for parts then finish up with git install of moodle.
But ... none of that is accessible to the outside world .. they are, however, accessible inside my home network by other workstations as well as my samsung android phone using local lan connection and samsung browser or FireFox.
Everyone else in here can help ... and appear to be assuming that the 'horse' is ok! Not being critical here guys - just not assuming the 'horse' is not configured like a 'nag' and acting like ready for 'glue factory'!