To create your notebook:
Go to Create New on Notebooks, or New Notebook when you are in the notebook list
Name your notebook. Additionally, you can add a description to your notebook. Also, you can select an existing tag (to connect your notebook with datasets and models) or create a new one.
You can now easily add and delete different text and visualization blocks (more about visualization). If you are not satisfied with the block position, you can easily move it. To speed things up, you can even clone each block. Your first Notebook is created and ready for exploring.