Your bonus video focuses on the infamous "background" Layer. This is sometimes confusing to new users so you will learn how it works and what it means to you. You will see how to manipulate the background as well as how to get around some of the limitations.
Lesson 9 shows you how to use the Shape layer by using the differing shapes that are available in Photoshop and how they use vector images and can resize easily.
Lessons 10-12 explain Adjustment Layers and how that they can really give you a lot of flexibility with your photos. These can make non-destructive changes to your images. There is also an explanation on how you can use gradients to mix skies and land for proper output. You will also learn how instead of using a gradient, you use a brush for a different effect.
Lessons 13-14 work with Layer mask and how they can finesse the photo to exactly what you want. Layer masking is just an evolution of what you learned from lesson 12. You will explore all of the variations on how to mask your layers to get a just right image. Your bonus lesson is all about aligning your layers.
Lessons 15-16 dive into Photoshop Blending layers and modes. Blending works like opacity on steroids, you will learn how to use Blend modes to blend two pictures into one and how to use Layer Blend modes to fix photos.
Lessons 17-20, cover special effects such as working with Layer Styles. It covers Smart Objects which allow you to work on an object with and still undo the changes after it has been saved. Smart Filters, which are normal filter plug-ins that work on Smart Objects, are explained. And Clipping masks; that functionality that allows one layer to be overlaid on another, is examined.