What do these files mean and how should I replace?

Question

In order to get into Symphony framework I had to install Virtual Box (VB) and Vagrant and SSH into the Ubuntu system I created with the default values of Puphpet. In order for my application to work correctly and remove the annoying '500 internal server error' from my pages, I need to replace a configuration file. It turns out this configuration file is cyan colored and has the '@' symbol behind it. How should I replace it with a custom config file and also make the custom config file look like the original one (from green to cyan aswell)? Do I need to read up somewhere what the cyan color means and/or what the @ symbol means in Ubuntu?

At least what I know about that cyan color means it's something that's called symbolic link.

An image displaying what my folder looks like now:

Edit: More information about the file here. Do I need to change permission of file to make the second config file match the third one in this example of commands (I suppose using chmod)?

Answer 1

In this context, the @ after a filename marks it as a symlink.

Specifically, under PuPHPet, everything inside /etc/nginx/sites-enabled is a symlink to a file under /etc/nginx/sites-available.