How does a Turbine generate energy?
By spinning its Rotor.
The fluid from the Turbine Vapor Fluid Tank is pumped into the Rotor chamber at the rate you configured in the Controller graphical interface.
A small amount of the vapor is captured by each Rotor Blade, causing the Rotor to spin.
When the Induction Coils are engaged, energy is generated depending on the Rotor speed and the average values of properties like efficiency and drag amount of all your coil blocks.
Please note that, while this overview allows you to create the best Turbines possible, it is an oversimplification of what's really going on inside your Turbine.