I have setup my VPS server with clients, and my own client is admin. And it is easy to create several other clients. The path to my domain is /home/admin/mydomain/.
All folders below mydomain will be owned by admin/admin (admin/apache also work). For permissions general rule is that all folders be set to 755 and all files to 644.
I am by no means an expert. I am self thaught and spent noumerous hours to search this forum and other internet sites. I have several times run into problems with the setup, been frustrated from time to time but also realized that most of the problems was due to my own misstakes. So I recorded the steps for a successful installation and I have created a 35 page Kloxo-MR Server Configuration Guide for Linux Beginners which also include installing Webmin, firewall etc.
I will not publish it here, but I can share it to you. Or better, if you register to my newly created website at
https://www.lundeco.com then we can discuss further there. It has a video conferencing capability and email and chat functionality, and we can use this to discuss. That way you can also help me test my website, which is actually a learning portal for online courses.
AJ