How to find the sum of the forces in the y direction of an elevator?

A cardboard box rests on the floor of an elevator. The box has a mass m = 3.75 kg and the elevator has an upward acceleration of a

Part a. Select the Free Body Diagram for the system

Part b. Write an expression for the sum of the forces actinv on the box in the y direcion, given that up is the positive y direction. Your answer should be in terms of FN, m, g.

Part c. Write an expression for the normal force FN, that the block experiences in terms of the elevator's accelaration, the block's mass and the accelaration of gravity

Part d. If the elevator's accelaration has a magnitude of g in the downward direction, what would the normal force FN1 be in Newtons? (Numerical value)

Part e. If the elevator's accelaration had a magnitude of g in the upward direction, what would the normal force FN2 ve in Newtons? (Numerical value)