Hi, what you did works but for future reference, if you didn't already know, Minecraft allows you to layer packs on top of each other. This pack is intended to be used on top of the regular Easy Blocks texture pack. To do that, just apply both packs at once on the right column in the resource packs screen, with Easy Dark on top of Easy Blocks so it will override the default Easy Blocks gui. Also, responding to your first question - you can do whatever you want with the files as long it's for personal use, I don't care.