3D Map Floor multiple quads

Hello, I use OpenGL 3.3. I want to know how i can have a floor made of more than one quad in my Map. I mean the part of the floor i can see should have multiple quads. For the quads on the floor i use quads that have a Expansion in x and z direction. So at the Moment my Exemple Quad is Not Visable. So how can i make that the quads i See Start at the bottom of the screen and have an ankle to the y direction of 15 degree. With the ankle i want to make the quads visible, because with Out ankle it is Not possible. If you Could give me answer with Code and Explantation would be Great. I use c++ as Programming language.
Thank you very much