Most repaints come with install instructions & sample Aircraft.cfg entries. If instructions are included it's best to follow them. If not my Add a Repaint tute might help.
http://www.simviation.com/lair/Repaint2002.htm

It was written for FS2002 but the principle is exactly the same. The folder names can be anything you wish providing they follow the FS folder naming conventions. Texture.3, Texture.green, Texture.easyjet etc. The part of the name after the period is what you add to the texture= line in the new Aircraft.cfg entry.