Install Python Jupyter Notebook on Debian

Perform system update:

sudo apt update && sudo apt upgrade

Install Python3 and PIP3:

sudo apt install python3 python3-pip

Install Jupyter:

sudo apt install python3-notebook

Jupyter Notebook Web interface:

jupyter notebook

Open the browser and point it to http://127.0.0.1:8888
To create a new notebook file, on the right side select New > Python 3 and start writing your code.