They are just simply editing and replacing files.
To open & edit .dds files: Download Adobe Photoshop and install this plugin:
To open & edit .tga files: Paint.net
To edit maps you need tools and knowledge.
If you want to try it out, you are welcome to edit BrokenWar private server client files and try them out ingame since we allow modding. If you try to edit specific files on the official warrock server you might get a ban. Just warning you in advance.
