These are the instructions if you just want to follow the latest NumPy source, but you don’t need to do any development for now.
The steps are:
From the command line:
git clone git://github.com/numpy/numpy.git
You now have a copy of the code tree in the new numpy directory.
From time to time you may want to pull down the latest code. Do this with:
cd numpy git fetch git merge --ff-only
The tree in numpy will now have the latest changes from the initial repository.