Hi:
Please go back to Chapter 2. It was my understanding that the Basics demo repository was created in Chapter 2. If you look in Chapter 2, at the demo entitled "Creating a Data Management Studio Repository", you'll see that the Basics Demo repository is created. Then in the Exercise in Chapter 2, that immediately follows this demo, your exercise is to create a similar repository to hold your exercises.
Here's a screen shot that shows the instructions for creating the Basics Demo repository.
And, here:
If you don't repeat the demo steps, you won't have the Basics Demo repository.
Hope this helps,
Cynthia