pathway for templating

What is the exact pathway for templating Cyclone Slider 2? I understand the concept because I’ve made two child themes, but the CSS changes I tested in Firebug are not taking effect.

I tried following the author’s instructions and made a pathway:
childtheme/cycloneslider/myrtle/style.css

When that didn’t work, I tried the full pathway of the plugin:
childtheme/cycloneslider/templates/myrtle/css/style.css

When that didn’t work, instead of “cycloneslider”, I tried using the exact name of the plugin as it appears in my plugins folder: cyclone-slider-2.

1)What is the exact correct path?

2)Do I have to copy every folder and file from myrtle into my theme, or is it enough to copy just the file that I want to modify?

3)To modify the template’s css, is it sufficient to modify just the css file of the template I’m using, or do I have to modify the css file common to all the templates as well?