Gent and Tom have answered the specific question, but it’s also worth mentioning that this is one of a list of questions covered on the DLS FAQ Thread. If you’re just getting rolling here, that is worth a look just to see what is on the list. Not all of it may be relevant now, but could come in handy later.
Also note that there was a lecture called “A Quick Introduction to the Jupyter Notebooks” and a reading item called the Programming FAQ. This point about how the “state” of the notebooks work was covered there. If you skipped those to save time, perhaps it was not a net savings of time. 