The given picture illustrates the way in which hydro-electric power is generated.
Overall, there are multiple stages in the process, beginning with heating seawater, and ending with hydro-electric power being sent to relevant infrastructure.
In the initiall stage, the sun shines heat the seawater, causing the sea to evaporate and form clouds. When the clouds accumulate enough water, they move into mainland and create rain. Following this, the rainwater is kept in a resevoir that is surrounded by a dam in order that the water not spill. In addition, the resevoir is also connected to a valve. If the valve is open, the water flows down the hill and through the turbine, making the turbine spin to generate electricity.
The next stage is that electricity is transmitted through high voltage cables to a transformer station which converts the voltage level from high to low. After that, electricity goes through underground cables to various places ranging from hospitals to schools. An extra point to note is that after going to the turbin, the water is pumped back to the resevoir and repeat itself.