Where are the materials for course 3754334?

I just started learning about Unreal Engine and am following along in this course:

One of the first steps is to download things from the marketplace which I did.

However when I started the “Using Developer Materials for Level Design” the narrator starts showing objects in the “Materials” folder that I don’t have.

The previous steps in this course doesn’t show anything in the “Materials” folder.

I was wondering if anyone knows where they are?