Heard about opportunity through Target jobs - applied online, including specifying my preferences for areas to specialize in (eg sovereigns, corporates, structured finance) and took online numeracy test a couple of weeks later.
Telephone interview was a couple of months later. I had found out a couple of days beforehand the date and time of the interview, including the fact that I had been assigned to a different area than I'd put down on my application form. The interviewer was very polite and kind, expressing that he knew I'd not chosen this subject so did not ask anything too technical. The interview was mainly motivational - weaknesses and strengths, what you would contribute to a team, etc.
A week later I heard via telephone call that I'd been accepted to one of two assessment centres, which was scheduled for a week afterwards. After confirming my attendance I was emailed the topic of the presentation I was told to prepare for - which country is most likely to exit the Eurozone. The presentation was told to be prepared to be roughly 10 minutes long, with a 20 minute Q&A session directly afterwards. At the assessment centre, there were two other assessments aside from the presentation - a 2 to 1 interview and an analytical task. The assessment centre took place all in one morning, with the opportunity to meet with the interviewers at the lunch provided.