creating a single beam spectrum using FFT

i am trying to plot a single beam spectrum using Fourier transforms the set of data's that i have is collected by an FTIR spectrometer. this datas are in a binary format and i have been able to view the interferogram of this binary file but getting the Fourier transform of it has been difficult and confusing, if anyone has any helpful code or even a hint on how to complete this task, i will be really grateful. thank you