It feels a little unintuitive, because the part is a square tube, but you can use the function Circular pattern. Select the holes on one plane as elements to repeat, select 4 repetitions and as turning axis the axis along the tube, then the holes get placed in the desired fashion.
First of all, welcome to Stack Exchange Engineering!
I think what you're looking for is how the forces work through the tool, not power transmission (which is work over time; power transmission would be more like power going through a flexible Dremel attachment). But this is a great question, and recognizing that it isn't just a simple thing puts you way ...
Many ways of transmitting power, mechanical with a steel cable with opposing winds or hydraulics using oil or compressed air come to mind. A datasheet for a product will explain the product but not always all the details of the parts used to make it.