I used some test data and the output of my Fourier transform should be correct (assuming that the test data I found on internet is good of course). The issue I have is that I am not exactly sure what the output represents.
The Fourier transform outputs a list of complex number and I should be able to use these complex number to find the amplitudes and frequencies of the sine waves that makes up my input.
I'll have some more research to do before I can use the Fourier transform to my advantage.