Django is not installed by default. Django is a webframework written in the language python. Python is installed by default. To install django, there are essentially two ways to proceed.

1. Use the Ubuntu package manager

Ubuntu has a version of django in its package system. If you just want to play around with django and learn what it is (and maybe do a simple project or two) you can run

sudo apt-get install python-django

2. Use pip and PyPi, the Python package manager

In the django community the standard procedure for most developers would be to use pip. Pip is "a tool for installing and managing Python packages." You can install it as follows:

sudo apt-get install python-pip python-dev build-essential 

sudo pip install --upgrade pip 

Once pip is installed you can type pip freeze in your terminal to see the list of packages installed. You can install django using pip install django.

There is one thing to note, though. This will install django systemwide (for alternative instructions, see How to install django?). Normally you would want to install django in a virtual environment. There is a bit of a learning curve to these tools, but they help you to get a good development environment.

sudo pip install --upgrade virtualenv 

http://www.saltycrane.com/blog/2010/02/how-install-pip-ubuntu/
http://warpedtimes.wordpress.com/2012/09/23/a-tutorial-on-virtualenv-to-isolate-python-installations/