A different issue is the ability to provide at all times proper instructions to the observers. This could be difficult either because the weather does not allow certain parts to be demonstrated, or because the observers (have to) use very different instruments. To allow for proper instructions also in these cases we plan to select a set of `example' images for each instrument that allows at all times to show how different procedures (how to define the proper focus, how to place a target on the slit or fiber, etc) work.