How to create a test site environment?

Question

Web development

We need a proven scheme / best practice algorithm .
Website
22 third-level domains (version for each country)
151 pages for each version
Size 18443 MB
Need to create a full test environment.
What is the best way to do this?
Whether locally in the office, or rent identical hardware from the host or?
Netcat - admin panel. Hoster - ihc, software - Debian 8 + ISPmanager 5