One of the hardest hurdles to clear with lighting design for theatre, is finding a way of communicating your ideas to the director and the rest of the design team.
You can’t build a model of how the lighting will look (at least, not without expensive software, and even then, it’s only a simulation).
It’s sometimes useful to use artworks as a reference for how the stage will look.
You can also use the natural world to inspire you, and to get your ideas across.