If I understand you correctly, you would like to view or download pdf files when clicking the relevant buttons from the grid command column in the example you referenced in your post.
To do that, you can specify appropriate href
attributes for the button anchors (since the buttons rendered in the grid are actually styled anchors, which you can verify by using your browser's development tools).
For further reference I suggest that you review the following online resources:
I hope these directions are helpful.
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