How do I read a chromatogram? 10 points best answer?

I have several chromatograms. I have a basic idea of how a GC/MS works, but I don't understand exactly what is the detector response and retention time. What does it represent? In simplest terms please! I'm only sixteen. I'm not learning this in class, I need to know for my science fair project.10... show more I have several chromatograms. I have a basic idea of how a GC/MS works, but I don't understand exactly what is the detector response and retention time. What does it represent? In simplest terms please! I'm only sixteen. I'm not learning this in class, I need to know for my science fair project.10 points best answer. Thanks in advance:)
Update: A.C. Thank you! It helps, but I still don't understand what detector response is, could you please explain to me what it is representing on the chromatogram? Is it the amount of that substance?
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