I installed and configured apache server on Linux VPS hosting and uploaded my old website to the new server. I did not point (yet) the domain name to the new IP address. When I click on the browser the new IP address, I don't see my website, but a default web page (I expected to see the website). Does that mean that the Apache server configuration is wrong or only if I change the IP address of the domain name, I will be able to see the website???
Most likely the server control panel software is configuring and Apache virtual host. And it sounds like the first vhost isn't also the default vhost.
To test to see if the vhost configuration is correct, without changing the global/public DNS, you can edit your hosts file where you are browsing from. /etc/host on Linux, C:\Windows\System32\drivers\etc\hosts under Windows. You may have to restart your browser.