By default template, do you mean the "It works!"-page you see when you do a fresh installation of Apache 2.x? If so, then you simply have to move/remove the files or change the ghost (000-default.con) in /etc/apache2/sites-available.
If the files are not located in /var/www/html, which they should by default if I recall correctly, then you could execute the following command to locate them, note that updated should be ran as root or with sudo!:
This should return all locations where html/index.html was found, and is most likely the default "It works!"-page you are currently receiving on your web server. You'll still have to find out which one exactly is the one that is being rendered, but that can be found in the default vhost-configuration-file. Try executing the following command:
This should return the exact location of the default vhost-file. You'll probably see 2 locations, one in sites-available and one in sites-enabled directory (not this is the default on Debian/Ubuntu destributions, these may vary on CentOS for example). The sites-available has all vhost-configuration-files, you can add new, remove or edit them. The sites-enabled has symlinks to the sites-available, but only of vhost's that are enabled (by executing a2ensite name on Debian/Ubuntu or sybolic link on CentOS (sudo ln -s /etc/httpd/sites-available/example.com.conf /etc/httpd/sites-enabled/example.com.conf)). If you do not have this default vhost-file or locations (sites-available and sites-enabled) on your system (probably on CentOS and distributions other then Debian/Ubuntu), you can edit your httpd-config file (default location: /etc/httpd/conf/httpd.conf) and add "IncludeOptional sites-enabled/*.conf" at the end of the file. This will put alle enabled vhosts into this particular directory. Make sure it exists!
You can check either version of the file, as they are exactly the same. You can do this by executing:
cat /path/to/file/000-default.conf | grep DocumentRoot
This should output the DocumentRoot included in that file. This is the root directory of this particular vhost, and in which you'll find your template-files.
But as I mentioned, the default location should be /var/www/html/, which is where you uploaded your website already. Is it possible that your website has a index.php and no index.html, as this would not override the default template file, thereby causing the web server to still return the index.html template instead. You can fix this by changing the DirectoryIndex in your apache2.conf-file.