Install python from this link https://www.python.org/downloads/
After this, install it on your PC. Look for the location where PYTHON has been installed on your PC using tge following command on your command prompt: cmd python.
Then go to advanced system settings and add new variable and name it as PYTHON_NAME and paste the copied path.
Then look for the path variable, select it's value and select edit
Add a semicolon towards the end of the value if it's not present and then type %PYTHON_HOME%