After Downloading Python 3.5 and the latest nightly build from http://tools.wmflabs.org/pywikibot/ I tried to follow https://www.mediawiki.org/wiki/Manual:Pywikibot/Installation#Configuring_Pywikibot
I did
> cd C:\Users\Jonatan\Desktop\pywikibot\core > pwb.py login
and got this result back
ImportError: No module named 'requests' Python module requests is required. Try running 'pip install requests'.
'pip install requests' doesnt work by default on Windows on Python 3.5
Instead instruct the user to do python -m pip install requests
(and the same for all other pip instructions)
An alternative is to just do the install for the user. At least on Windows.