How to run .py code in windows?

I am not able to run .py extension in my windows machine.
How to exceture .py script in windows?

If you already installed Python ,add python to the environment variable
open the command prompt and navigate to the folder where you stored the file
then type

python filename.py
If you don’t have python installed following link have step by step procedure to install it
Python Download and Installation Instructions

Thank You. I will try your steps.