Answer 1

it's just an .exe, if it doesn't work try to reinstall it and check "install in PATH" or something like that.
Then you would be able to call it for the cmd just by typing "py"

Answer 2

https://youtu.be/thURRPH_CVg
Hey you can follow these tutorial to install portion ide. This will be your last video and you will also learn how to write hello world program in Python.