Beggining module development

Hello everybody, i want to develop a module for FreePBX; i checked the wiki pages but i didn’t found any useful documentation or Howto; The only documentation that i found was for the module structure which is incomplete.
The framework also does not have a documentation. I wanted to know where should i start? Is there a howto or page that i missed??

Regards

Take a look at POSSA

github.com/POSSA