I am not clear what you want to ask but let me explain. Column in HPLC is like a separator of chemical compounds which release chemicals one by one.As one type of chemical come out through column and reach to detector it gives some absorbance till it pass through the detector cell. This absorbance Vs time is plotted on HPLC graph and it is a representation of one peak at that HPLC chromatogram . In similar way column elutes compound by compound and we get several peaks at HPLC chromatogram.