Possibility of using the APIs of libraries directly

I recently started learning about the OF and am really interested in getting more details about some specific questions.

  1. Is it possible to use the APIs of the libraries (say OpenCV) directly without the OF API’s in the code?
  2. Can I associate self made libraries to the project? Is there a documentation of how to associate source code?

Thank you in anticipation of your response,
Best Regards,