Put `x5o.el' in your Emacs load-path and add the line below to your .emacs file:
(require 'x5o)
You will need to have cask installed to run tests. Once it is installed:
git clone https://github.com/papachan/x5o.el.git
cd x5o.el
# install dependencies
cask
# run unit tests
cask exec ert-runner