To check whether you have python3 installed in your system use:
$ python3 --version
If that fails, it is most likely python3 isn't installed, but python2 is, in which case this should tell you the the version you have:
$ python --version
If python3 is not installed on your system, follow the instructions here: http://python-guide-pt-br.readthedocs.io/en/latest/starting/installation/
$ sudo xcode-select --install
Follow the instructions here: https://python-docs.readthedocs.io/en/latest/dev/virtualenvs.html
$ virtualenv --python=`which python3` interview.venv
$ source interview.venv/bin/activate
$ pip install -r requirements.txt
The requirements.txt mentioned is the one in this repo.
After those are is installed you are good to go.
If you'd like a quick check, follow these instructions on setting up a django project: https://docs.djangoproject.com/en/1.9/intro/tutorial01/#creating-a-project If you can run the development server and load the site on your browser you are good to go.