October Novel Prep Challenge

That's up to you. Where does your action take place, inside, outside, or both? The purpose of the settings exercises is twofold: (1) to practice writing believable setting descriptions, and (2) to clearly identify in your own mind as the author where the obstacles and props are that affect your plot. Technically, if your action takes place both inside and outside the building, those are two different settings, so you're welcome to split that into two exercises. If the action only takes place inside, you aren't required to describe the outside, but you're welcome to. It just gives you more practice.