How do you change the water pump on a vw 1.9 diesel transporter?

To change the water pump on a VW 1.9 diesel transporter, first, ensure the engine is cool and disconnect the battery. Drain the coolant, then remove the timing belt covers and the timing belt to access the water pump. Unbolt the old water pump, clean the mounting surface, and install the new pump with a new gasket. Reassemble by reversing the steps, ensuring proper tension on the timing belt, and refill the coolant before starting the engine.