It is easy to get a developer sandbox running for KARL3. (Deployment sandboxes are covered elsewhere.)
KARL3 is a repoze.bfg application, which means it needs Python and some core Python tools before starting.
These steps are fairly common for mainstream Python web development, meaning they are well-documented and reliable.
$ git clone git://github.com/karlproject/dev-buildout.git karl3
$ cd karl3
$ /path/to/your/python/bin/virtualenv --no-site-packages .
$ bin/python ./bootstrap.py
$ bin/buildout -U
$ bin/supervisord
After five or ten seconds, visit in your browser: http://localhost:6543/fs/ and login as username admin and password admin.
Much more installation information is available in the README.txt at the top of the checkout.
A writable checkout requires access to the github repository.
Once access is granted, check out the buildout as follows:
$ git clone git@github.com:karlproject/dev-buildout.git karl3
And then create the virtualenv and run the buildout as above:
$ cd karl3
$ /path/to/correct/virtualenv --no-site-packages .
$ bin/python ./bootstrap.py
$ bin/buildout -U
$ bin/supervisord