How the Azimuthal quantum number describes 3d shape of the orbital?
what they call 'orbital' of an electron in chemistry is called wave function in physics. It determines how the electron moves and how it behaves. In fact it determines everything of the electrons. The azimuthal quantum number is just the quantum number used to describe angular part of the wave function, so it determines the shape of the orbital. This is a very rough explanation. You need to learn something like quantum chemistry or quantum mechanics in order to get a better understanding on that.