Hi Veronica,
I believe the user has to be signed in into the Cloud for the Scratchbook space to work (?).
I decided to open a second window next to the browser and work the exercises in Mathematica. I need to take my time to type in instead of copy/paste (that did not work for me), it helps me to practice the syntax of the language. I also have a few tabs open at the Documentation Center to look up entries that I do not know about, or not understand, or to alter how graphs render for example.
I am also curious about how others approach the examples and the practice exercises.
I hope this helps. Be well!