If your domain and hosting company different you have to make connection with hosting and domain. If your hosting allows multi domain in your c panel than you have to set addon domain
The cPanel “Addon Domains” feature allows you to manage multiple domains from a single hosting account. Unlike with Parked domains, Addon domains are expected to be completely different websites all hosted inside the same cPanel account. You can also create additional sub-accounts (for example, email addresses) for your addon domains.
Even if you click on the File Manager link, you will see the default file in that folder.
If everything is correct, then the name servers will be changed within 5 minutes. However, it can take up to 24 hours until the changes are in effect.