I often use subdomains for development & testing (stage.somedomain.com). I need to confirm things are working there before pointing the DNS at my server and hosting the main somedomain.com. The main domain has approved content, so I don't want to use it for development and it needs to stay unchanged after the domain transfer. The staging subdomain lives on after the transfer so I can continue to work on it without affecting the main site, but I still need to access it before the DNS is changed.
On other servers, I've done this by aliasing a subdomain of one of my own domains which already exists on my server and pointing it at the not-yet-transferred stage.somedomain.com.
How can I do this in Plesk?
somedomain.com
(existing domain is hosted elsewhere and set up as a domain in Plesk to prepare for transfer)
stage.somedomain.com
(set up as a subdomain in Plesk)
somedomain.my-example.com
(Already hosted on Plesk, I want it to host content from stage.somedomain.com on my server.)