I have tried following the steps on the website but they're not working for me. At least I must be doing something for them not to work.
Firstly, before the steps, the site tells me to open the command line and type python --version. So I typed on the windows search bar 'command line'. Python (command line) came up and I went ahead and typed python --version and I got the error

python is not defined

along with other stuff. So I decided to try the command prompt, the second option to come up when I typed 'command line' in on my windows search. It returned saying that it was not recognized as an internal or external file.
I attempted step 1, just to try my luck, on both the Python command line and the command prompt and nothing really happened. I'm not really sure what to do now.
i have encountered a simillar setback while trying to install kivy on python.
in python version 3, py is used instead of python for launching python in the command prompt i.e
py (to launch python3) 
py -m pip install kivy (to install kivy) 
N.b: before installing kivy it is recommended to install cython and other python dependencies using py -m pip install cython
How to install kivy on Windows 10