Here's an example of 'Before and After' shots, showing what the Art Department does to a location. Our job is to make an environment that tells the story. And that allows the actor to inhabit the character in a believable way. Sometimes we find a location that doesn't require a lot of changes. Other times it's more of a blank slate.
Here is a shot of the place that would become Ellie's (Toni Collette's) desk at the offices of (fictional) Stax Magazine:And here's the same spot, after Set Dressing:
Here's a shot of the empty space that would become her apartment:
And here's the same room, during Set Dressing: