If you are specifically looking to move into an existing household of an individual / roomamte that is offering a room for rent, you can do that easily by going to the 'Find Roommates' page and selecting the filter "I'm looking for" as "Room for Rent" and clicking apply.
If you haven't signed up yet, and would like to just browse the availabe rooms for rent (by other individuals), just click below on the nearest metro area to you: