matplotlib is not a local file that is part of the assignment: it is a python package that needs to be installed in your environment. You had to install the Jupyter environment on your computer in order to even start the notebook, right? That’s only the beginning: you also need python, matplotlib, scipy, sklearn and eventually TensorFlow and so forth.
I’ve never actually tried running the notebooks locally, so I’m not the right person to help with this. My suggestion would be to try googling “how to install matplotlib locally” and see what you find.
There are also some threads on the forums that have instructions for this general process. Here’s one for example.