Download and Install Python at this link: https://www.python.org/downloads/
On Mac/Linux, it's likely already installed, or you could use the command line if you're comfortable with it.
Go to this website and search for Python as the language: https://repl.it/
Or just use the command line on Mac/Linux if you are familiar.
Install some sort of Python IDE
- IDLE is popular for beginners
- I think it comes pre-installed with the Python download here.
- Jupyter Notebook is popular for Data Scientists - It and many other tools come all packaged together with "Anaconda"