Setting up Vitualenv correctly

Hi there,

I'm working in Ubuntu 16.04, I have Anaconda python 3.6 installed and the default Ubuntu 2.7 installed, although to date I've only used version 3.6.

I'm using PyCharm 2017.2.4.

I want to recreate this project to do so I need to set up a python 2.7 virtualenv.

https://github.com/dumrauf/b2c2_client

This project will ultimately be run from the command line in Ubuntu, so I need to set things up so that python 2.7 (and the necessary packages) are available outside of the PyCharm environment, at the command line. I think the best way to do this is to set up a virtual environment is this correct?

Following the instructions here, I am trying to set up the appropriate virtual environment:

https://www.jetbrains.com/help/pycharm/configuring-python-interpreter.html

The part I am confused by is sub-steps 3 and 4 of step 3 of setting up a virtualenv in the link above:

Should I inherit the site-packages? Why does this mean in practice? Also it seems I don't even seem to have such a directory at /usr/lib/python2.7/site-packages, I have /usr/lib/python2.7 but no folder corresponding to /site-packages

Should I make available to all projects? Again what are the pros and cons?

Thanks Baz