It should be "shown", but I think you at least need a comma. Also, "a" should be "an": I will give you an instruction, shown below. While this is correct English, it is possibly not the most natural way of saying what you want.
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SSY Jung"Pesase see the instruction below." I've got it.Actually, my suggestion was "instructions". The plural would be more common here, and used, for example, when giving someone information about how to do something. As well as suggesting a single statement (rather than a list of steps to be followed), the singular tends to sound more formal or auth