Data Grid Or Data Matrix...

This seems a very complicated task, so I welcome any
input. My boss wants a data grid or matrix of the top 6
orders with ordered items, and products, for a particular
customer and he wants to see it like this:

products down the left side
orders across the top
number of items under the respective order number column
across from the corresponding product.

I hope that makes sense.
I have three tables. Products, Orders, Orderitems. I
don't even know where to start. Many thanks in advance
for any input offered.