Help with spectral analysis of a time series

I have a data set that contains surface elevation in meters and time in seconds. 
I need to convert this data into an energy spectrum with Frequency on the X axis and Spectral Density (Amplitude Squared/Frequency) on the Y axis.
I believe I need to use Fourier Transform to achieve this but am currently unsure how to do this, any help would be greatly appreciated.

Answer 1

[Pratyush Roy]

Hi,

The following link might be helpful:

https://www.mathworks.com/help/signal/ug/power-spectral-density-estimates-using-fft.html

Hope this helps!