First I installed Python 3.5.2 (32 bit) for Windows 10, because I was taking an online Python 3 course through ed2go. This installation of Python is also called CPython.
But then I wanted a more robust development environment on Windows. I found Visual Studio Community. Rather than take the defaults, I chose "customize" so I could get Python, among other things. It looks for now like I've got Python.
Also I turned on developer mode. To do this, I typed "developer settings" into Cortana. Then I selected "Developer Mode" and said yes to their disclaimer. I rebooted at this point. I'm not sure I needed developer mode.
I needed an outlook account, apparently, to sign into Visual Studio. I created one.