You are purchasing the book and access to the videos, not the full kit.
Throughout the book we refer to yarn and other products that are included with the Beginners Box box but since this is the book/videos only, you’ll need your own supplies.
We have used Yarn and Colors Super Must Have yarn which is a 100% cotton yarn in 7 different colours.
We’ve used various sizes of crochet hook so would recommend you try whichever sizes you are comfortable with depending on the yarn you choose.
You’ll also need a darning needle, scissors and pins.