layouts how use it

I wonder how layouts work, I thought it was as java is what they do from the gui interface or in some pieces, such as north, south, west, east, can anyone get me out of doubt, to serve layouts and if they have any use for a programmer.

Think of a layout as a repetitive content on your pages. The layout will contain same header and footer through your application with some minors changes (ie SEO details, titles, and so on…). Layout as ‘in java term’ is not but it could be set as such if you configure it so (CSS), and then render content as specified by you…

http://www.yiiframework.com/doc/guide/1.1/en/basics.view#layout