Connect 3rd party open source platform with our application

Our application offers educational content. A third party open source platform is used by many educational institutions to manage their courses. We would like to develop a plugin for the 3rd party platform, which makes it possible to offer our educational content of our application directly in the 3rd party platform. With the plugin it should be possible for every course to offer a list of links to content in our application, where the content can be viewed finally. Some additional information has to be displayed automatically near the link (e.g. image thumbnail, short description). On the other hand, we would like to collect information (e.g. course name, institution ID, user ID) from the 3rd party platform when the content has been clicked by a student to perform evaluation. For our application a mini-API has to be developed which allows sending and receiving data to and from the 3rd party platform. Both systems are based on PHP, MySQL, JS. Our application uses ExtJS framework for UI. Both projects are in German language as well as the documentation of 3rd party platform for plugin development, so some knowledge of this language will be very useful, because we cannot offer any translation. The 3rd party platform is available for free download in several versions. The developed plugin should work at least with the last 2 versions. You’ll have to download and install the 3rd party platform for development. We have prepared screenshots and a simple flowchart to support your development and visualize our expectations. (see atached file). We are looking for an experienced PHP/MySQL developer which has no problem to understand existing code and application structure. Patience and high professionalism are welcome. Please describe shortly why you are the right one for this project. If you like, you may short describe your proceeding.