[Ayantir]

Looked quickly at it and ...

http://wiki.esoui.com/Main_Page
http://wiki.esoui.com/Getting_Started
http://wiki.esoui.com/Writing_your_first_addon
http://wiki.esoui.com/SimpleNotebookTutorial/part1

I would also say that when you don't understand something, look at how others did and do same.