How to develop an UI, please: some questions

[Mathias]

Greetings all!

I'm a C# programmer and I want to try to create my own EQ2 UI.

So, I've been reading the official documentation found in the ZIP file "UIBuilder.zip".

After reading it I've been looking at the default skin code and what I found was XML.

I don't understand very well how to code your own UI... what programming language you've to use in order to code an UI? Is it all made using XML?

Thank you in advance!