I was recommended by a previous employer, so for me it was very simple. One informal interview "Why I want to work for Sberbank?", "Salary expectations", "How can you contribute?" Then a few weeks to check my identity and an offer. However, for some technical interview, the process and the questions may be very tough as there are a lot of physicists and mathematicians working. So be ready for brain teasers, data structures, statistics, probability theory and stochastic calculus.