Create a box shape using dimensions of all three axes.
The length of the box measured from the pivot point in X direction.
The width of the box measured from the pivot point in Y direction.
The height of the box measured from the pivot point in Z direction.
The box will be created with the base face on the working plane, so consider setting up the working plane before starting.
Select Create Box from ribbon menu.
Select the first corner of the box on the working plane.
Select the second corner on the working plane. This will define length and width of the box.
Select the height by picking a point on an axis running trough the last selected point.
The pivot point is always set such that the dimensions are all positive in the local coordination system of the box.