I read about how to change the interface for KR. It is really that easy to change a interface. I am not that good with computers but it look eaay enough. There is anything else besides .....

Getting Started

1.) Locate the UserInterface folder. It will be in the install directory for UO Kingdom Reborn.
2.) Extract Default.zip to the UserInterface folder. This archive contains the source layouts and artwork that you will be modifying.
3.) Make sure that the extraction process created a Default folder under UserInterface.
4.) Create a new folder under UserInterface with the name that you want to use for your Custom UI.
5.) At this point you can begin copying files over from the Default folder and making modifications to them. (Make sure you maintain the same directory structure)

....that I need to know

This is not an area in which I am very proficient, perhaps these links will help guide you.

UOSkins.com
XML Tutorial

Good luck my friend.

In most cases yes ... replacing files works. As long as you understand how to copy files in and out of the correct folders.

Be wary however, to save a copy of your original files so you can go back, since you may not like the look of the new theme you just installed.

Also most of the skins will come with instructions of what to do.