I've tried, but I'm not very good with xml.
Actually, I was the same way back yonder. But take something like the main menu screen, usually screen xml's are in the main "skin" directory, so if you look for the menu.xml, or main.xml (you can always find the screen name from the skin editor), you can get a good understanding of the information presented in the xml. Eventually, you will realize how things are done more and more.
What's neat too, is that once you start to understand it, you can look at almost any other program that uses xml, and feel comfortable editing the information.
Just keep practicing, you'll catch on to it before you know it.