Split content into a subdomain

I have a standard Kirby setup, which has a few directories:


I now need to split out one of these into a subdomain, e.g.


I would like this still to be managed by the Kirby installation at project.com, and also have any directories within still work, e.g.


should show the content from


What would be my best approach for achieving this? Thanks for any help

Basic setup: Quicktip: Serving a page on its own domain | Kirby CMS

I have read that cookbook entry, and am afraid I am going to need a bit more guidance if that is ok.

My site is all complete, in public_html on my cPanel hosting. When I set up a subdomain I have to point that to a directory on the hosting, where should that be? And do I need to duplicate / move my Kirby index.php as well as making the alterations from the cookbook entry?

Thanks for your help.