Did I install floor wrong???

I installed a laminate floor over concrete, and there is thick padding between the floor and the concrete. I assumed the guy at Menards knew what he was talking about when he told me the padding would act as a vapor barrier. Should I have put a layer of plastic between the padding and the floor? I have a problem with small gaps appearing between pieces of the floor. Thanks.
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Never listen to the guy at Menards. Read the installation instructions.

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There are pads that also act as the vapor barrier. If you put the right stuff down, you are OK. What does the manufacturer recommend?
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