The App Library contains a series of app collections, which are created automatically based on categories such as Entertainment and Productivity..
These are displayed in blocks of four icons, in mini two by two grids. Each block generally contains three app icons and a folder containing the rest of your apps in that category.
Like a web page, not all of the content is on screen at any one time, depending on how many apps you have installed of course. So you can scroll with three fingers to find more.
You can quickly skip through the categories using the Containers option in the VoiceOver rotor.
However when doing this, the page is not automatically scrolling as it should when you reach the bottom of what is currently displayed.