Magento Go is loaded with predefined places where you can place content. Each location has a name, or block reference that identifies the place on the page, within the context of the page layout. In this section, you will learn two different methods for positioning blocks with layout updates.
The code that controls the page layout and placement of content blocks is written in XML. You may have noticed references to XML Page Layout Updates throughout the Admin panel of your store. Every product, category, and piece of content—whether it‘s a page, block, banner, or app—has a section where you can update the XML code that controls the placement of the item. The selection of available block references varies by page.
The advantage of using a frontend app is that you can select from a variety of options, without having to remember all of the possible combinations or syntax.