Spectroscopy Control System for Elements

Hello I have a design project in Electrical and Electronic Engineering. That I need to know how to plot wavelength-intensity graph for some elements. For example, like copper and carbon (etc...) so Where should I start from ? and I have to calculate area between lower and upper point of element. Also I am not a proffesional Matlaber so I need help.

[Onur Hakverdi]

here is a basic code