The Codility Test is not complicated. You can practice in the Codility website (2 hours, but 1.20 hour is enough )
In the Technical Interview, they ask you about your knowledge of the company, what they do, the products they offer. Not difficult but it is important to review a lot their website, and trading concepts.
Important, some technical questions about Patterns, Multithreading, and Low Latency, as well as your work experiences.
In the third step you have to solve a Cube Puzzle, they told me that It can be done in 4 - 6 hours, but no more that 16 hours., In my humble opinion, 4 - 6 hours is not realistic. Maybe between 10 h. if you have experience with puzzles. There are three questions, one mandatory, and two additional questions. Important to define a good structure of your project, using testing cases.
Despite the fact that I solve the puzzle, I didn't receive a feedback, either a response to my several emails. So I decide to continue with other companies.