Lower Switch for Ground tank water level sensor. Middle switch and upper switch for upper tank low and full water level sensors.
If upper tank water level lower than low water sensor and ground tank was full. the water pump will running and when water level over the low water level sensor the water pump will keep running and when reach to full water level sensor the water pump will stop. When water reduce and water level lower than full water level sensor the water pump still keep stop and when water level lower than low water level sensor the water pump will running again. While the water pump running if ground tank out of water (water level lower than sensor) the water pump will stop and resume running when water level over the sensor (water full in ground tank).
