Implement LTI tool in php

I am developing a Learning Management System in PHP and I am willing to integrate LTI tools like Questionmark(http://ift.tt/1Hq0qBR) in this application but I am very new to LTI and even do'nt know from where and how I should start.

So, please share any demo application if there or any better tutorial for it if anyone has. Thanks in advance.

via Chebli Mohamed