Pointing a domain to your server usually means creating or editing an A or AAAA record at your DNS provider so the domain or hostname resolves to your server IP address. Depending on your setup, you may also need web server configuration, SSL, reverse proxy rules, or mail records.
Make sure the service on the server is actually listening and ready before you change live DNS. DNS alone does not make the application available if the server software is not configured.
After the DNS change, allow time for propagation and test from more than one network.