YUI is one of finest work from YAHOO!. That’s the reason why Liferay Alloy UI is based out of it.
So a default question comes to your mind, how I can start using YUI library. Here it goes.
If you know JQuery very well and its just a matter of time for you. Just Visit the URL and get started with YUI.

Your expression doesn’t look comfortable, so you want another site to start with YUI. Here it goes.

Are you a Liferay User ? waana want to start with, this link may help you find your answer.