Convert time domain to frequency domain Harmonic analysis

Hi all

I have an a.c. non-sinusoidal signal/waveform as a table of samples taken at a certain number of samples per cycle i.e. it has an unknown number of harmonics of unknown magnitude in the signal.

I want to derive the value of each harmonic which I can put in a bar chart with frequency or harmonic number as the horizontal axis and the magnitude as the vertical axis.

I have tried the Data Analysis Tool Pack <<Fourier>> function which returns a set of complex numbers which doesn't make any sense to me.

I have constructed a test waveform using 4 harmonics and summating them to generate a set of samples .. but in real life I would only have that sum column of samples to work with i.e. the harmonic content is unknown.

I want to take that summed column and generate a bar chart showing the individual harmonic component and its magnitude like the sketched one attached