Add Second Domain to Server

I need assistance with adding a second domain to my server. I currently have a working domain (e.g., blahblah.com) and want to add another domain (e.g., blahblah2.net) on the same server. Both domains should point to the same website content, and it's not a simple forwarding setup. I attempted to do this myself but got stuck and need this done urgently.

Key Requirements:
- Configure the server to host two domains with identical content.
- Ensure both domains are accessible independently.
- Avoid simple domain forwarding; both domains should be fully functional.

Ideal Skills and Experience:
- Strong understanding of web server configuration, especially with Media Control Panel, Apache/Nginx software.
- Experience in managing multiple domains on a single server.
- Ability to edit and configure server files effectively.
- Quick problem-solving skills to address urgent needs.

I have full access to the server's configuration files, so you can make the necessary changes. However, I need guidance on how to configure the software if required. Your expertise in this area would be greatly appreciated.