I Need Help With A Simple Modeling Issue

[bev.lynn]

I am trying to create granite/belgian block edging as shown in this pic.

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I created a chamfer box that's adequate for my needs and I have a bump/displacement map to deform the box. I cannot figure this out! I know this is simple, but I am still learning. I have attached the max file and the bump/displacement map. Can someone please tell/show me how to do this? Ultimately I will apply a matte arch & design material.