Well I started with Unigui at 2012 (almost 9 years ago) It took me a while to understand how it works and especially how to mix Ext code with Unigui, I spent a lot of time in the Extjs API documentation and read a lot of books about Sencha Extjs and posted a lot of question in their forum and in Stackoverflow and in most cases I answered my self :-).
Unigui is great and amazing framework that's nothing else can come even close to it.
Always there is a first time, In my projects I don't retype css or client-side code I just copy & paste and modify as necessary.