I need help with problem B can someone explain this to me in details i am confused

Demand: Thinking Like a Buyer End of Chapter Problem

The marginal benefit received for each kilowatt hour (kWh) of electricity consumed per week for Ang, Tony, and Gianna are provided in the accompanying table.

a. On the first graph, move the points to plot an individual demand curve for each person.

b. Assuming there are only these three people in the market, create the market demand curve for electricity on the second graph. Move each of the points of the market demand curve provided to plot the appropriate market demand according to the dataset provided. Round down to the nearest whole kWh for each consumer.

kWh consumed perweek	Ang's marginal benefit	Tony's marginal benefit	Gianna's marginal benefit
1	$7	$4	$8
2	$5	$3	$6
3	$3	$2	$4
4	$1	$1	$2