In this chapter, we introduced the concept of layering. We learned about the directory structure in detail and the content of each layer type. In addition, we saw how to add an external layer to our project manually or by using the BitBake command line, as well as how to make use of the OpenEmbedded Layer index to easily find the available layers that we need.
In the next chapter, we will learn more about why we need to create new layers and what the common metadata included in them is (such as machine definition files, recipes, and images), and wrap it all up with an example of distribution customization.
