How to install ERPNext "inside or on" KeyHelp?

Hello to all out there!

My Name is Jerome and I am from Austria. I try to install ERPNext “inside” KeyHelp.
KeyHelp (www.keyhelp.de) is a Server Management Software like Plesk or ISPConfig.

The challenge is now, how to install ERPNext at a explicit user “inside” KeyHelp. I mean, with KeyHelp you can manage Customers on a Webserver. And one customer wants to have installed ERPNext on his “instance”. I hope it is possible to understand what I really mean?

I would be very thankful if anybody can help me with that issue!
Thank you very much!

All the best from Austria
Jerome