Sphinx on Windows

The GHC wiki says you need Sphinx to build docs, https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation/Tools and refers to the Preparation doc for how to install Sphinx https://ghc.haskell.org/trac/ghc/wiki/Building/Preparation But the Windows sub-page of Preparation does not say how to install Sphinx. Question: how does one install Sphinx on Windows? The sphinx-doc home page mutters about 'pip', but I've never used that. Does anyone have instructions? Thanks Simon