You are in a dark world. You have a window / alcove you can peer into. In the window, there are disembodied hands that form a sign and show an image that this sign represents [how to show the image will be interesting].

If you learn the sign, and make the same sign over / near that item out in the dark world, that item / area becomes illuminated.

These are simple signs, not a full language. Much like the signs used by monks in the 2nd century. In fact, it might be a good idea to see how many of those signs could be incorporated. The scene could in fact by a monastery.

Symbolic light and dark world meaning.