All the abilities of the older versions are there. You just work with or invoke them differently. (Here’s a recent post pointing out some of the newer details vs the older routes at this time.) And so it may take a bit of looking around to translate the steps done in the video you are following. Feel free to post here again if you get stuck in doing that.
One of the biggest differences will be in what is supported by extensions. That will improve over time. For example, a Table of Contents is now built in, see here and the original post in that thread. That used to be one of the unofficial contributor authored notebook features that you could add, see here. Now you get that and other advances built in.
That is probably the best idea as someone starting in Jupyter now.
And if later you decide you want something that is more along the line of a full-featured interactive development environment experience, you can try JupyterLab. It has a single document mode you can toggle into and out of, too.