This is a bootstrap library for developing actions for Appzio using PHP. It includes an example module + some of the shared libraries. If you are developing for Appzio, contact devsupport@appzio.com to get your own server instance, sftp access and all the other related goodies.
You don't need the Yii installed, but it will make your life little bit easier if you are using a proper IDE. If you have composer installed and working (sorry, need to use without https, if its not enabled do "php composer.phar config secure-http false" first.) Simply do "php composer.phar install".
Good partner for this toolkit is the rest bootstrap library (https://github.com/appzio/rest-bootstrap-php) and iOS / Android application which is connected to your dev instance.