How to create a new notebook using the Python 3 kernel?

I am following the tutorial at: https://blog.finxter.com/introduction-to-web3-py/

It says that:

How to Connect to a Local Ethereum Test Network

Start Jupyter Notebook by running the command below.

(venv) $ jupyter notebook

The default web browser will automatically open the Jupyter notebook home page. Create a new notebook using the Python 3 kernel.

As mentioned above, we will use a test Ethereum network running in the local environment for demonstration purposes. To connect to the local Ethereum network, we can use Web3.EthereumTesterProvider() as shown below.

from web3 import Web3

w3 = Web3(Web3.EthereumTesterProvider())

print(w3.isConnected())

I can’t understand:

a)how to create a new notebook using the python 3 kernel:

My current terminal is executing jupyter notebook, I tried opening a new terminal and typing: $ Python 3 kernel, but its giving me errors:

Command ‘Python’ not found, did you mean:

command ‘jython’ from deb jython

command ‘cython’ from deb cython

command ‘python’ from deb python3

command ‘python’ from deb python

command ‘python’ from deb python-minimal

b)where to write the command:

from web3 import Web3

w3 = Web3(Web3.EthereumTesterProvider())

print(w3.isConnected())

Somebody please guide me.

Zulfi.