Applied online.
1 week later, was invited to take an online IQ type test, which was straightforward and mostly knowledge independent (some basic graph theory helps with a very small number of the questions, but not worth spending time on if you don't already know it).
2 weeks after taking the test, I received an email that I was through to the next round, a phone interview, which happened 1 further week later. Phone interviewer was pleasant. Started with general questions about my background, why Bloomberg and the usual stuff then some technical questions. This interview is about knowing data structures and algorithms with minimal emphasis on coding. Nothing to be scared about.
Unfortunately, I blew it by preparing for the wrong thing/nervousness over first interview so no details about later rounds.