In order for a website to appear on a domain, the folder for the domain must contain the files that will generate the website in the visitor's browser.
Where to place the website files for the main domain on the hosting?
The main domain on the hosting is the domain associated with the hosting package, and the hosting package is named after that domain.
The default folder for the main domain is: /public_html
The absolute path (if needed) is: /home/USER-NAME/public_html
Once you upload the website files to the /public_html folder, the site will be accessible at the main domain address.
Note: Upload the files directly to the folder. If you mistakenly place the files in a subfolder inside the /public_html folder, the site will not be available at DOMAIN.NAME but rather at DOMAIN.NAME/subfolder.
Where to place the website files for an additional domain?
All other domains, besides the main domain, should have their own separate folders.
When adding the domain, you will need to specify which folder it will use.
In that folder, you will need to place the website files.
You can find the guide for creating an additional domain [here].