Second domain name, please help!

Hi, my boss purchased a new domain name: digitalnameplates.com that currently re-directs you to our company’s website homepage: https://www.roemerind.com. He asked me to create another “homepage” for the new domain he registered. Is it possible to create a new page for the new domain that maintains all of our current wordpress themes/appearance? Do I have to start from scratch since it’s a separate domain name? I have very limited knowledge with wordpress so any help would be greatly appreciated!