Best practice for setting up new test SEPM?

Attempting to test the upgrade from 12.1.6 to 14 but not ready to do this in production. Trying to establish a test environment and need the best way to achieve this. Will be on same network, same Windows domain, unfortunately.

I suppose the question is should this be a separate "site" or what? Separate SQL DB I'm sure. Is there a document somewhere that addresses this?

Thanks in advance.