When your domain is set up on the server / webspace, a subfolder named "www.IHREDOMAIN.tld" is automatically created, containing a file named "index.html".
The "index.html" file contains a placeholder page with the text: "Hier entsteht die neue Webpräsenz von "IHREDOMAIN.tld""
Once your domain's DNS settings point to the server, the "index.html" file will be publicly accessible.
Once you have uploaded your website to the appropriate subfolder, you must remove or rename the existing "index.html" file.
By default, the following files are served as the "default document":
index.html
index.htm
index.php