This question is related to water footprint calculation. I have no idea how to go about this, if anyone could point me in the right direction, I'd be forever grateful!

Background info:
The water footprint of the resident of a Blue Sea riparian country (92 million residents, watershed area 2.6 million km2 ) expressed in the area required to provide the respective service of the Earth system as well as green water flow is: the precipitation of 750mm on area of 400 m2 per year is sufficient to provide at the present consumption habits, drinking and industrial water; 1300 m2 per year of lake and 5900m2 per year of river are needed for the sustainable natural treatment of waste; wood products consumed for heating, house - building, newspapers etc. need a green water flow of 18000m3 per year and a person needs a green water flow of 1300 m3 per year for healthy diet (food). Calculate and answer the following questions:

Question:
a) The transpiration flow through plants for food production is about 260L per square meter per year and 472 L per square meter per year for the forest (wood products). Calculate the areas needed for the food and wood products production.(1 mark)

b) Calculate the total required area (water footprint) per resident of the Blue Sea region. This area will supply every person with the necessary water-supported services in this region. Show your calculations.(2 marks)

aw, guys someone help me please??