Create New PHP MVC modules to an existing small project management system

I purchased a small project management system that manages clients and projects. The I need to expand that system with new modules to add more functionality. ## Deliverables I will require clear concise documentation on the modules. The documentation will show: 1. What the modules are 2. How the modules work 3. How the modules are called 4. How the modules work I will narrow my choice of developers to 3 and provide access and details.