Getting started document:
You can download a basic getting started guide on the http://demo.flstudio.com page.
FL Studio help file:
You can also consult the online help file on our site or in the FL Studio program itself (F1 key on your keyboard).
FL Studio beginner tutorials on YouTube
Both FL Studio 11 & 12 work in the same way. Only on FL Studio 12 you see new graphics.
From our own Image-Line YouTube channel:
FL Studio - Getting Started Tutorial
From our power user Varian:
From our power user Seamlessr: