I pulled this from a previous post of mine and added a bit to it.
The following is all done through the transform window in the graphics menu. No need to select points off of CAD or anything else before rotating/translating wherever you want.
When in transform, you can choose to translate to a single surface. Click the "Select" box in the translate area of the rotate/translate dialog box. You have several options, including (I think) point 1, point 2, and checkboxes for X,Y,Z. Deselect the x and y checkboxes, ignore everything else, and click on the surface you want to set your z origin to. (Assuming you want it to be Z origin. Click ok to exit the box, and click apply.
To do a 3D translation, go into the same thing and click on a corner point. It should grab it. If it doesn't grab it first time, you need to click in the dialog box to tell it you are reselecting point 1, because otherwise it changes so your next click on CAD will be point 2.
The only time you would select a point 2 would be if you are translating by an increment on the cad model, such as a step height.
To rotate, you follow similar instructions, but you need a point 2 to build the line you are going to rotate to.
Hope this helps. It took me a looong time to understand the CAD rotate/translate options.
