Unable To Edit Files In Root Directories

I am using Whonix as development OS. I need to be able to edit, copy and paste files into the root directories to configure software. For example I need to paste sites-available in /etc/nginx/ but the files open as read only and I cant paste into any folders outside of /home/ that I’ve tried. On other Linux distros I use sudo nautilus and edit files as root but Whonix says there is no nautilus so I have no idea how to change these files.

So if nautilus isnt installed then whats the file manager? I thought nautilus was in all versions of linux

Excuse my brevity due to lack of time on my side. If parts of my post are unclear, please kindly use search engines. By putting thunar into a search engine, you’ll find out what that is.