Add PDF Chat to My AI Saas

Please do not bid if you have never worked with the Openai Api before. I have an ai saas. I want to add a feature of the user to upload a PDF and chat with openai about the contents of the PDF. My saas is written php and the openai library we are using is the "orhanerday" which is widely utilized. Once we complete this, I have other features I would like to work on as well.