Please could you explain to me how to solve this exercise

Consider a modified cogeneration power plant with regeneration. Steam enters the turbine at 6MPa and 450C at a rate of 20Kg/s, and expands to a pressure of 0.4MPa. At this pressure 60% of the water vapour is extracted from the turbine, and the rest is expanded to a pressure of 10KPa. Part of the extracted steam is used to heat the feed water in an open feed water heater. The rest of the extracted vapour is used for process heating, and leaves the process heater as a saturated liquid at 0.4MPa. It is then mixed with the feed water leaving the feed water heater, and the mixture is pumped to boiler pressure. The vapour in the condenser is cooled and condensed by cooling water from a nearby river, which enters the adiabatic condenser at a rate of 463Kg/s. Consider the ideal equipment and demonstrate the enthalpy values shown

a) The temperature rise of the river cooling water in the condenser is: (R=8C)

b) The mass flow of steam through the process heater is: (R=10.4 kg/s)

c) The process heat to be obtained (KW) R=16,487.52 kW