Problem with MIDI Yamaha YGP-625 READ PLEASSE?

I am an 11 month vet of FL Studio and decided to go out and get me a Yamaha YGP-625. Now, by *going out* meaning I bought it from a relative since it was in their studio and they never used it. It is almost in Mint, nothing wrong with it, although it was bought years ago. No CD to be found, or remembered to have by my cousin. I tried going online to find drivers, as I am a Computer Savvy person, and yet to have found out.

TL;DR How do I get a driver, and FL Studio to work for my Yamaha Please detail!