How do I move my primary domain out of the public_html folder?

I’m new at this, but trying very hard, I hope you can help with this…

I recently asked my host to change my primary domain, which they did, and the previous primary domain is now “parked”. As a consequence, my new primary domain, that I would like to use to create a brand new website, is displaying exactly the same content as the previous one.

Can anyone tell me what files I should move from the “public_html” folder and to what destination so I can finally free my new domain from the other one..?

Thanks