Calculate and plot exponential Fourier series coefficient

So I have to evaluate the Fourier series coefficients using Dn = 0.25e^(-jn*(pi/4))*sinc(n*(pi/4)) then plot the magnitude Dn (in volts) and phase Dn (in degrees) of the first twenty-one coefficients versus fequency (in rad/sec).

Can someone please help me!

Please provide as many steps and explanations as possible. Im going to study using the notes provided.

Thank you in advance!!