The whole application process consist of four stages. First you will need to fill in the application form online, then the phone interview, the first round in-house interview and a final round interview with the head of the department.
The application form
The Bloomberg application form is not difficult to fill in. A good CV is absolutely necessary and if you got that, and justify your reasons why you want to be in Bloomberg and what you can bring to Bloomberg, then there should not be any problem for you to get the phone interview.
The phone interview
The phone interview consist of questions that are mostly covered in this website. My telephone interview lasted only around 15 mintues, which you can imagine that it's not something too difficult or very in-depth if you have done your preparation beforehand. Basically they will go over your CV, ask you why you want to work in Bloomberg, and things like that. My advice is to get to know what Bloomberg does (know it really well because they will definitely ask), know why you want to work for this department. (try to find out what the financial sales and analytics department do and map it onto your interest!)
The first in-house interview
The first round interview was held in Bloomberg's London office. There were 10 people in the group, which some of them were sociable while some of them were quite nervous. Two junior person from Bloomberg became our "guides". At first, we were brought to a room where a manager gave us a brief introduction of what Bloomberg does. (You should already know about what Bloomberg does already because you are supposed to have done your homework! So try not to rely on his presentation on Bloomberg to get to know the company). Then we were taken by our "guides" for an office tour to see the fish tanks, art decorations, the kitchen etc. After the office tour, we were splited up individually and taken by two other senior persons from the department for a 2:1 interview. Both of my interviewers were from the Sales department. Basically, this round of interview is to test on your knowledge of Bloomberg, why are you interested to work in Bloomberg, and go over your CV in greater depths than the phone interview. They do test people on financial knowledge so remember to know something about the financial markets beforehand. And if you do not have a finance background, remember to say this to them so that they won't ask you lots of technical financial questions, but at least you should be able to present a chapter from the finance text book. In my interview, I was asked a lot about customer services, sales, and why I was interested in Sales in Bloomberg. Be prepared for examples. I was also asked "How can I sell Bloomberg to a group of strangers in a room when you have no time at all to prepare"
The final round interview
In my confirmation email from the HR, they said that the head of the department plus another person would be my interviewer, but it turned out that only the head of the department interviewed me. This time, the interview was not as nice and friendly as the first interview, where I had time to explain my motivations and interests. Basically what you need to prepare for this round is very similar to the first round in-house interview, but with more interuptions when you deliver your message to the interviewer. I was interrupted for a few times, which made me more nervous. I was asked questions about my experience, why I was so interested in the work the Bloomberg does in that particular department, an example to prove that I am good at communication skills, another example on leadership skills, a test on my problem-solving ability on the spot (be prepared, it can be anything!), and he asked me to explain the recent financial crisis to him.