First step in quick start guide doesn't link to further setup instructions for migen about misoc HOT 2 CLOSED

Indeed, Migen is a python module, you can then use pip or any other tool able to process setuptools meta data (in setup.py).
If you want to contribute, then the best way to install it is using : python3 ./setup.py develop --user

There is a documentation for Migen, which contains an "install" instruction : https://migen.readthedocs.org/en/latest/introduction.html#installing-migen

It states that for simulation, you also need to install the VPI module.

Migen can also be installed via conda : https://binstar.org/fallen/migen
However, as the migen conda package is not update automatically yet, it can be outdated and you should prefer the "install from git clone" solution.

from misoc.

There currently still isn't a clear path from the README.md in the misoc directory to the install instructions at https://migen.readthedocs.org/en/latest/introduction.html#installing-migen

See m-labs/migen#13

from misoc.