The developer guides at the Paypal Integration Center describe the Payflow Pro API fairly well, and include examples in PHP. If you read through the Payflow Pro Developer's Guide, you will see many examples of using the API.
If you are expecting to cut some code from the Developer's Guide and paste it into your PHP app, you are going to be disappointed. Online payment processing is a huge industry; there are dozens of merchant banks, payment processors, specifications, workflows, card suppliers, versions, fraud and security services, human and programming languages, and best practices available. It is not possible to have a table of every permutation implemented for every business. Even if such a thing existed, no human would live long enough to read it.
You have to determine your workflow ahead of time, read through the Developer Guide, pick out the APIs for the features you need, and implement them. Work through Paypal's Integration Overview step by step. This is not a simple process, you are probably looking at weeks of work.
I suggest reconsidering the "they will not be leaving our website" requirement. The Payment Card Industry guidelines for handling credit card and personally-identifying information is very hard to implement. You will also have to leave the origin site to support 3D-Secure.
If this is your first project using online payments and is time-critical, I really suggest using a hosted payment service, like the Paypal shopping cart, and not trying to implement it yourself. Online payment processing is a complex problem, and the results of mistakes can be catastrophic. If you absolutely must implement it yourself, consider hiring a consultant with previous experience.