There’s going to be obvious things that you can do to design the space: poster-like graphics that you can lay across walls, customizing theater wayfinding signage, taking over all the lightboxes with one-off graphics from your system but there’s also the unique opportunities for the space that you choose and that might constitute another round of micro-research (i.e., making a list) so we'll start with that.
Make list of all the things that you can put in a space. Start with the obvious (poster, LED signs above theater entrances, floor graphics) but then progress to any physical things that you can put in the space that are relevant to your project.
Example: Emily might have picture frames, science books, those old-school pulldown periodical table things, actors headshots, chalkboards, etc
The easiest way to start the actual project is to find good quality photographs* of spaces that look believable for your project. You do NOT have to use the actual space that you’ve chosen for the project, you just need the inside and outside to feel coherent. On the other hand if your program takes place at a local landmark the Heights theater, your photos should feel like the Heights (i.e., don't use a big old modern theater complex) so that interviewers don’t get caught up in that part of the presentation.
Review the photos. What can you do with the space?
Figure out how to render these elements. For 2D graphics, you can estimate the proportions and produce a graphic in InDesign or Illustrator and then export it as a JPG and place it into Photoshop to do any distortion. 3D objects are trickier and will probably require a Photoshop collage technique. That said you can also draw the spaces and then place the graphics or objects in (or draw the whole thing). Drawings are actually preferable because your photography is probably copyrighted (in which case, don’t put online. Just use it in your live presentations). I recommend that you do an image search for architectural rendering techniques because there’s a wide variety of ways to approach communicating space.
* Don’t get too caught up in the “good” photos. If you can't find anything, then just make sure you have descriptive images that you can work from to make some kind of drawing-based image.