If you want student housing, apply for it now on the school website. They'll email you details sometimes next year before school starts. Although it's a bit pricier than places around town, it is actually convenient, so most students do stay on campus, which is why I recommend you to apply now. If you decide you don't wanna stay on campus later, you can always cancel you application whenever. The only place people discuss options and look for roommates would be the official Class of 2024 ARCOM Facebook group, so you can join it now if you want, but these discussions probably won't happen till around sometime between April-July next year. Also I think if you apply for a 2 beds and say you need a roommate, when the time comes, they'll actually send you a list of all the people that also need a roommate.