Under Modelling you will find Model Settings. On the 3. Tab there, called "Modelling Helper" you will find this:
The Show 3d obj Model is not functioning, i havent found a good exemple how to load a obj into the opengl surface.
The other 3 Functions are working. Use load to select a bitmap, and mark Show to display it. The use the Scrollbars to Place, Rotate and Scale it. And when finished use save and load to save it for the next time.