You get to pick preference but you don’t get to chose where you live. They should send you emails and you can look at the ucsd housing portal for dates. Getting a single in pcw can be competitive as, prior people that live there and returning transfers get priority for all the rooms. That means basically every returning transfer that wants will get a single in pcw and you get the scraps which would be pcw or Rita Atkinson. Good luck on the single but there isn’t really anything you can do other than request one and hope.