The reason for the “dataset missing” error is that (as Saif says) you need a lot more files than just the notebook. From one of the running notebooks, click “File → Open” and you’ll get a file navigation view of all the supporting files that accompany the notebook. There is a topic on the DLS FAQ Thread about how to download all the files using a pretty easy method. There are no official instructions for how to install all the software you need if you want to run locally, but here’s a thread that will get you started that applies to DLS anyway. As you’ll see from reading that thread, it’s not a simple matter.
Maybe Colab is an easier path. I’m in the same position as Saif on that: I haven’t actually tried it with the course assignments. I have used it a bit though and one thing to point out is that you need to upload the course files to your Google Drive and then Colab references them from there. You may have to modify some code in the notebook to get the pathnames to work out correctly given the differences between Colab + Google Drive versus the way things work in the course Docker images.